xwayland: Add xwl_cursor_clear_frame_cb()

The code to clear a cursor pending frame callback was duplicated in
multiple places in the code.

Introduce a new xwl_cursor_clear_frame_cb() function and remove the
duplicated code.

No functional change.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Carlos Garnacho <carlosg@gnome.org>
5 jobs for xwayland-cursor-cleanup in 6 minutes and 23 seconds (queued for 4 seconds)
Status Name Job ID Coverage
  Docker Image
passed debian-buster #15070495

00:00:15

 
  Build And Test
passed autotools #15070496

00:06:07

passed meson #15070497

00:02:45

passed meson-noglamor #15070498

00:01:32

passed mingw-cross-build #15070499

00:00:44