arch/arm/mach-w90x900/cpu.c: replace obsolete strict_strto

Replace obsolete strict_strto with kstrto calls

Signed-off-by: Daniel Walter <dwalter@google.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>