jhbuild: Don't build broken impact driver
jhbuild: Don't build broken impact driver

xf86-video-impact has been broken for a while and isn't built by
build.sh. Move it to the unmaintained metamodule until someone cares.

Signed-off-by: Dan Nicholson <2570c412b7cbb4203ff39baaca2bd49e72848226@gmail.com>
Reviewed-by: Dirk Wallenstein <0094b88488405ee50298c1549891ed49bcd7831f@t-online.de>

freedesktop-unofficial-mirror/xorg__util__modular,freedesktop-unofficial-mirror/xorg__util__modular,freedesktop-unofficial-mirror/xorg__util__modular