litest-alps-semi-mt: Fix compiler warnings

litest-alps-semi-mt: Fix compiler warnings

This fixes the following (false positive) compiler warnings:

litest-alps-semi-mt.c: In function 'alps_touch_move':
litest-alps-semi-mt.c:163:3: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
   send_abs_mt_xy(d, r, b);
   ^
litest-alps-semi-mt.c:163:3: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized]
litest-alps-semi-mt.c: In function 'alps_touch_down':
litest-alps-semi-mt.c:127:3: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
   send_abs_mt_xy(d, r, b);
   ^
litest-alps-semi-mt.c:127:3: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized]

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>