xwayland: always include drm.xml in tarballs

Move drm.xml out of the automake conditional so make dist includes it
even if glamor-egl is disabled.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83960

Signed-off-by: Julien Cristau <jcristau@debian.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Keith Packard <keithp@keithp.com>
(cherry picked from commit af40913797e6595fb5466c2ff3110e9526a37b9f)
Bump to 1.16.1

Signed-off-by: Julien Cristau <jcristau@debian.org>