Input: i8042 - select ARCH_MIGHT_HAVE_PC_SERIO on IA64

Architectures which might use an i8042 for serial IO to keyboard,
mouse, etc should select ARCH_MIGHT_HAVE_PC_SERIO.

Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>