remoting: Use DRM FourCC formats instead of GBM formats

The remoting plugin currently has a set_gbm_format() hook, which accepts
GBM_FORMAT_* tokens from the host to set as a supported format.
GBM_FORMAT_* values are strictly aliased with DRM_FORMAT_*.

In order to avoid an extra unnecessary dependency from the remoting
plugin on GBM, switch to using the formats from libdrm instead.

This fixes a compile error seen when the remoting plugin is enabled:

    ../remoting/remoting-plugin.c:39:10: fatal error: gbm.h: No such file or directory
       39 | #include <gbm.h>
          |          ^~~~~~~
    compilation terminated.

The error was caused by not having any dependency at all on GBM from
the remoting backend, which is fixed here by adding a new dependency on
the libdrm headers for drm_fourcc.h.

Signed-off-by: Daniel Stone <daniels@collabora.com>
5 jobs for remoting-remove-gbm-dep in 3 minutes and 6 seconds (queued for 10 seconds)
Status Job ID Name Coverage
  Container Prep
passed #920415
container_prep

00:00:26

failed #920300
container_prep

00:00:11

failed #920297
container_prep

00:00:11

 
  Build
passed #920298
build-native-meson-default-options

00:01:19

passed #920299
build-native-meson-no-gl-renderer

00:02:39