xwayland: Fix crashes when there is no pointer

When running with a weston session without a pointer device (thus with
the wl_seat not having a pointer) xwayland pointer warping and pointer
confining should simply be ignored to avoid crashes.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
4 jobs for wip/sjoerd/xwayland-crash-nomouse in 9 minutes and 59 seconds (queued for 1 second)
Status Job ID Name Coverage
  Docker Image
passed #3396716
debian-testing

00:00:50

 
  Build And Test
passed #3396717
autotools

00:09:09

passed #3396718
meson

00:02:22

passed #3396719
meson-noglamor

00:02:09