Input: inport - use correct config option for ATIXL

Change the apparently incorrect check for CONFIG_INPUT_ATIXL
in a source file to be consistent with the kernel config
option CONFIG_MOUSE_ATIXL.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>