xwayland: do not auto-lock pointer when rootful

Xwayland tries to be smart and guess the intention of the X11 clients
sometimes, like issuing a pointer lock when a client hides the pointer
when confined.

While this is a good thing when running rootless, this is problematic
when running rootful as the pointer will be automatically locked unless
the "retro" mode is used (which doesn't hide the cursor, unlike the
default).

Make sure we don't trigger the automatic pointer lock when the cursor is
hidden when running rootful.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>