drm: Add DisplayPort colorspace property creation function

drm: Add DisplayPort colorspace property creation function

Because between HDMI and DP have different colorspaces, it adds
drm_mode_create_dp_colorspace_property() function for creating of DP
colorspace property.

v3: Addressed review comments from Ville
    - Add new colorimetry options for DP 1.4a spec.
    - Separate set of colorimetry enum values for DP.
v4: Add additional comments to struct drm_prop_enum_list.
    Polishing an enum string of struct drm_prop_enum_list
v5: Change definitions of DRM_MODE_COLORIMETRYs to follow HDMI prefix and
    DP abbreviations.
    Add missed variables on dp_colorspaces.
    Fix typo. [Uma]
v6: Addressed review comments from Ilia and Ville
   - Split drm_mode_create_colorspace_property() to DP and HDMI connector.
v7: Fix typo [Jani Saarinen]
    Fix white space.
v8: Addressed review comments from Ville
   - Drop colorimetries which have another way to distinguish or which
     would not be used.
v9: Addressed review comments from Ville
   - Split hunk into renaming and adding of code.

Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190919195311.13972-5-gwan-gyeong.mun@intel.com