[Why]
ABGR16161616 colour format was added to dcn10/20/30, and set
any ARGB16161616 to the same value as it (26). As such, the
HDR10 Green Point y value was too far off of the EDID stated
value for DisplayPort.

[How]
Added back the pixel format as 22 for ARGB16161616 for
dcn10/20/30.
Reviewed-by: Reza Amini <reza.amini@amd.com>
Acked-by: Solomon Chiu <solomon.chiu@amd.com>
Signed-off-by: Ethan Wellenreiter <Ethan.Wellenreiter@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>