Input: convert obsolete strict_strtox to kstrtox

With commit 67d0a075

 we mark strict_strtox
as obsolete. Convert all remaining such uses in drivers/input/.

Also change long to appropriate types, and return error conditions
from kstrtox separately, as Dmitry sugguests.

Signed-off-by: JJ Ding <dgdunix@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>