intel_idle: Add __init annotation to matchup_vm_state_with_baremetal()

The caller of (recently added) matchup_vm_state_with_baremetal() is an
__init function and it uses some __initdata data structures, so add the
__init annotation to it for consistency.

This addresses the following build warnings:

WARNING: modpost: vmlinux: section mismatch in reference: matchup_vm_state_with_baremetal+0x51 (section: .text) -> intel_idle_max_cstate_reached (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: matchup_vm_state_with_baremetal+0x62 (section: .text) -> cpuidle_state_table (section: .init.data)
WARNING: modpost: vmlinux: section mismatch in reference: matchup_vm_state_with_baremetal+0x79 (section: .text) -> icpu (section: .init.data)

Fixes: 0fac214 ("intel_idle: Add a "Long HLT" C1 state for the VM guest mode")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>

Author: rafaeljw

drivers/idle/intel_idle.c

@@ -2147,7 +2147,7 @@ static void __init intel_idle_cpuidle_devices_uninit(void)
  * All our short idle states are dominated by vmexit/vmenter latencies,
  * not the underlying hardware latencies so we keep our values for these.
  */
-static void matchup_vm_state_with_baremetal(void)
+static void __init matchup_vm_state_with_baremetal(void)
 {
 	int cstate;