arch/x86/mm/kmemcheck/kmemcheck.c: use kstrtoint() instead of sscanf()

Kmemcheck should use the preferred interface for parsing command line
arguments, kstrto*(), rather than sscanf() itself.  Use it
appropriately.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>