mm: remove unneeded kallsyms include

mm: remove unneeded kallsyms include

The file was converted from print_symbol() to %pSR a while ago in commit
3a81bb2d7da7 ("mm: Convert print_symbol to %pSR").  kallsyms does not
seem to be needed anymore.

Link: http://lkml.kernel.org/r/20171208025616.16267-3-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>