drm/connector: Allow drivers to pass list of supported colorspaces

Drivers might not support all colorspaces defined in
dp_colorspaces and hdmi_colorspaces. This results in
undefined behavior when userspace is setting an
unsupported colorspace.

Allow drivers to pass the list of supported colorspaces
when creating the colorspace property.

v2:
 - Use 0 to indicate support for all colorspaces (Jani)
 - Print drm_dbg_kms message when drivers pass 0
   to signal that drivers should specify supported
   colorspaecs explicity (Jani)

v3:
 - Move changes to create a common colorspace_names array
   to separate patch

v6:
- Avoid magic when passing 0 for supported_colorspaces;
  be explicit in treating it as "all DP/HDMI"

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Sebastian Wick <sebastian.wick@redhat.com>
Reviewed-by: Joshua Ashton <joshua@froggi.es>
Reviewed-by: Simon Ser <contact@emersion.fr>

Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Sebastian Wick <sebastian.wick@redhat.com>
Cc: Vitaly.Prosyak@amd.com
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joshua Ashton <joshua@froggi.es>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Simon Ser <contact@emersion.fr>
Cc: Melissa Wen <mwen@igalia.com>
Cc: dri-devel@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>