Input: sh_keysc - add mode 4 and mode 5 support

Add Mode 4 and Mode 5 support to the SH_KEYSC driver. These modes allow
slightly larger key pad matrixes.

While at it, make use of resource_size().

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>