mm: remove mm_init compilation dependency on CONFIG_DEBUG_MEMORY_INIT

Towards the end of putting all core mm initialization in mm_init.c, I
plan on putting the creation of a mm kobject in a function in that file.
However, the file is currently only compiled if CONFIG_DEBUG_MEMORY_INIT
is set. Remove this dependency, but put the code under an #ifdef on the
same config option. This should result in no functional changes.

Signed-off-by: Nishanth Aravamudan <[e-mail]>
Cc: Nick Piggin <[e-mail]>
Cc: Mel Gorman <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

mm/Makefile

···
 			   maccess.o page_alloc.o page-writeback.o pdflush.o \
 			   readahead.o swap.o truncate.o vmscan.o \
 			   prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
-			   page_isolation.o $(mmu-y)
+			   page_isolation.o mm_init.o $(mmu-y)
 
 obj-$(CONFIG_PROC_PAGE_MONITOR) += pagewalk.o
 obj-$(CONFIG_BOUNCE)	+= bounce.o
···
 obj-$(CONFIG_TINY_SHMEM) += tiny-shmem.o
 obj-$(CONFIG_SLOB) += slob.o
 obj-$(CONFIG_SLAB) += slab.o
-obj-$(CONFIG_DEBUG_MEMORY_INIT) += mm_init.o
 obj-$(CONFIG_SLUB) += slub.o
 obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
 obj-$(CONFIG_FS_XIP) += filemap_xip.o

mm/mm_init.c

···
 #include <linux/init.h>
 #include "internal.h"
 
+#ifdef CONFIG_DEBUG_MEMORY_INIT
 int __meminitdata mminit_loglevel;
 
 /* The zonelists are simply reported, validation is manual. */
···
 	return 0;
 }
 early_param("mminit_loglevel", set_mminit_loglevel);
+#endif /* CONFIG_DEBUG_MEMORY_INIT */