tools/Makefile: do missed s/vm/mm/

Commit 799fb82 ("tools/vm: rename tools/vm to tools/mm") missed
renaming 'vm' in 'tools/Makefile' to 'mm'.  As a result, 'make clean'
under 'tools/' directory fails as below:

    $ make -C tools clean
      DESCEND vm
    make[1]: Entering directory '/linux/tools/vm'
    make[1]: *** No rule to make target 'clean'.  Stop.
    make[1]: Leaving directory '/linux/tools/vm'
    make: *** [Makefile:173: vm_clean] Error 2
    make: Leaving directory '/linux/tools'

Do the missed rename.

Link: https://lkml.kernel.org/r/20230415203110.13858-1-sj@kernel.org
Fixes: 799fb82 ("tools/vm: rename tools/vm to tools/mm")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Ricardo Pardini <ricardo@pardini.net>
  Link: https://lore.kernel.org/linux-mm/20230415202454.13558-1-sj@kernel.org/
Tested-by: Ricardo Pardini <ricardo@pardini.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: sjp38

tools/Makefile

@@ -39,7 +39,7 @@ help:
 	@echo '  turbostat              - Intel CPU idle stats and freq reporting tool'
 	@echo '  usb                    - USB testing tools'
 	@echo '  virtio                 - vhost test module'
-	@echo '  vm                     - misc vm tools'
+	@echo '  mm                     - misc mm tools'
 	@echo '  wmi			- WMI interface examples'
 	@echo '  x86_energy_perf_policy - Intel energy policy tool'
 	@echo ''
@@ -69,7 +69,7 @@ acpi: FORCE
 cpupower: FORCE
 	$(call descend,power/$@)
 
-cgroup counter firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
+cgroup counter firewire hv guest bootconfig spi usb virtio mm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
 	$(call descend,$@)
 
 bpf/%: FORCE
@@ -118,7 +118,7 @@ kvm_stat: FORCE
 
 all: acpi cgroup counter cpupower gpio hv firewire \
 		perf selftests bootconfig spi turbostat usb \
-		virtio vm bpf x86_energy_perf_policy \
+		virtio mm bpf x86_energy_perf_policy \
 		tmon freefall iio objtool kvm_stat wmi \
 		pci debugging tracing thermal thermometer thermal-engine
 
@@ -128,7 +128,7 @@ acpi_install:
 cpupower_install:
 	$(call descend,power/$(@:_install=),install)
 
-cgroup_install counter_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
+cgroup_install counter_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install mm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
 	$(call descend,$(@:_install=),install)
 
 selftests_install:
@@ -158,7 +158,7 @@ kvm_stat_install:
 install: acpi_install cgroup_install counter_install cpupower_install gpio_install \
 		hv_install firewire_install iio_install \
 		perf_install selftests_install turbostat_install usb_install \
-		virtio_install vm_install bpf_install x86_energy_perf_policy_install \
+		virtio_install mm_install bpf_install x86_energy_perf_policy_install \
 		tmon_install freefall_install objtool_install kvm_stat_install \
 		wmi_install pci_install debugging_install intel-speed-select_install \
 		tracing_install thermometer_install thermal-engine_install
@@ -169,7 +169,7 @@ acpi_clean:
 cpupower_clean:
 	$(call descend,power/cpupower,clean)
 
-cgroup_clean counter_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
+cgroup_clean counter_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean mm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
 	$(call descend,$(@:_clean=),clean)
 
 libapi_clean:
@@ -211,7 +211,7 @@ build_clean:
 
 clean: acpi_clean cgroup_clean counter_clean cpupower_clean hv_clean firewire_clean \
 		perf_clean selftests_clean turbostat_clean bootconfig_clean spi_clean usb_clean virtio_clean \
-		vm_clean bpf_clean iio_clean x86_energy_perf_policy_clean tmon_clean \
+		mm_clean bpf_clean iio_clean x86_energy_perf_policy_clean tmon_clean \
 		freefall_clean build_clean libbpf_clean libsubcmd_clean \
 		gpio_clean objtool_clean leds_clean wmi_clean pci_clean firmware_clean debugging_clean \
 		intel-speed-select_clean tracing_clean thermal_clean thermometer_clean thermal-engine_clean