fs: includecheck fix: proc, kcore.c

fix the following 'make includecheck' warning:

  fs/proc/kcore.c: linux/mm.h is included more than once.
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/proc/kcore.c

@@ -23,7 +23,6 @@
 #include <asm/io.h>
 #include <linux/list.h>
 #include <linux/ioport.h>
-#include <linux/mm.h>
 #include <linux/memory.h>
 #include <asm/sections.h>