gbm: remove gbm_gallium_drm from the loader

No longer used as of commit 48c7461d5a0(st/gbm: remove state-tracker)

v2: Add commit message.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Kristian Høgsberg <krh@bitplanet.net> (v1)
1 file changed