s390/sclp: Move memory hotplug code for better modularity

To improve readability and prepare for future extensions, move the
memory hotplug code to a separate file. In addtion to it, add required
headers in sclp_mem.c and remove unnecessary headers in sclp_cmd.c

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

Author: sumanthkorikkar

drivers/s390/char/Makefile

@@ -21,6 +21,7 @@ obj-y += ctrlchar.o keyboard.o defkeymap.o sclp.o sclp_rw.o sclp_quiesce.o \
 	 sclp_cmd.o sclp_config.o sclp_cpi_sys.o sclp_ocf.o sclp_ctl.o \
 	 sclp_early.o sclp_early_core.o sclp_sd.o
 
+obj-$(CONFIG_MEMORY_HOTPLUG) += sclp_mem.o
 obj-$(CONFIG_TN3270) += raw3270.o con3270.o
 obj-$(CONFIG_TN3270_FS) += fs3270.o