drm/amd/display: Send PQ bit in AMD VSIF

[WHY & HOW]
PB9 bit 5 was added to signal PQ EOTF in AMD vendor specific infoframe.
This change sets it when appropriate.

Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Krunoslav Kovac <krunoslav.kovac@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>