drm: Add HDMI colorspace property

drm: Add HDMI colorspace property

Create a new connector property to program colorspace to sink
devices. Modern sink devices support more than 1 type of
colorspace like 601, 709, BT2020 etc. This helps to switch
based on content type which is to be displayed. The decision
lies with compositors as to in which scenarios, a particular
colorspace will be picked.

This will be helpful mostly to switch to higher gamut colorspaces
like BT2020 when the media content is encoded as BT2020. Thereby
giving a good visual experience to users.

The expectation from userspace is that it should parse the EDID
and get supported colorspaces. Use this property and switch to the
one supported. Sink supported colorspaces should be retrieved by
userspace from EDID and driver will not explicitly expose them.

Basically the expectation from userspace is:
 - Set up CRTC DEGAMMA/CTM/GAMMA to convert to some sink
   colorspace
 - Set this new property to let the sink know what it
   converted the CRTC output to.

v2: Addressed Maarten and Ville's review comments. Enhanced
the colorspace enum to incorporate both HDMI and DP supported
colorspaces. Also, added a default option for colorspace.

v3: Removed Adobe references from enum definitions as per
Ville, Hans Verkuil and Jonas Karlman suggestions. Changed
Default to an unset state where driver will assign the colorspace
is not chosen by user, suggested by Ville and Maarten. Addressed
other misc review comments from Maarten. Split the changes to
have separate colorspace property for DP and HDMI.

v4: Addressed Chris and Ville's review comments, and created a
common colorspace property for DP and HDMI, filtered the list
based on the colorspaces supported by the respective protocol
standard.

v5: Made the property creation helper accept enum list based on
platform capabilties as suggested by Shashank. Consolidated HDMI
and DP property creation in the common helper.

v6: Addressed Shashank's review comments.

v7: Added defines instead of enum in uapi as per Brian Starkey's
suggestion in order to go with string matching at userspace. Updated
the commit message to add more details as well kernel docs.

v8: Addressed Maarten's review comments.

v9: Removed macro defines from uapi as per Brian Starkey and Daniel
Stone's comments and moved to drm include file. Moved back to older
design with exposing all HDMI colorspaces to userspace since infoframe
capability is there even on legacy platforms, as per Ville's review
comments.

v10: Fixed sparse warnings, updated the RB from Maarten and Jani's ack.

v11: Addressed Ville's review comments. Updated the Macro naming and
added DCI-P3 colorspace as well, defined in CTA 861.G spec.

v12: Appended BT709 and SMPTE 170M with YCC information as per Ville's
review comment to be clear and not to be confused with RGB.

v13: Reorder the colorspace macros.

v14: Removed DP as of now, will be added later once full support is
enabled, as per Ville's suggestion. Added Ville's RB.

Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1550596381-993-2-git-send-email-uma.shankar@intel.com