ci: build mesa with gbm

We need gbm support for piglit.
Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <mesa/mesa!7370>

.gitlab-ci.yml

@@ -732,7 +732,7 @@ meson-android:
     UNWIND: "disabled"
     DRI_LOADERS: >
       -D glx=dri
-      -D gbm=disabled
+      -D gbm=enabled
       -D egl=enabled
       -D platforms=x11
       -D osmesa=false