drm/amd/display: Wrong colorimetry workaround

[Why]
For FreeSync HDR, native color space flag in AMD VSIF(BT.709) should be
used when intepreting content and color space flag in VSC or AVI
infoFrame should be ignored. However, it turned out some userspace
application still use color flag in VSC or AVI infoFrame which is
incorrect.

[How]
Transfer function is used when building the VSC and AVI infoFrame. Set
colorimetry to BT.709 when all the following match:

1. Pixel format is YCbCr;
2. In FreeSync 2 HDR, color is COLOR_SPACE_2020_YCBCR;
3. Transfer function is TRANSFER_FUNC_GAMMA_22;

Tested-by: Mark Broadworth <mark.broadworth@amd.com>
Reviewed-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Ma Hanghong <hanghong.ma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>