drm/amd/display: VSC SDP supported for SST

drm/amd/display: VSC SDP supported for SST

[why]
If a typeC to HDMI dongle supports YCbCr420 pass through and VSC
colorimetry and pixel encoding formats in the Extended Receiver
Capability, we shall allow VSC SDP to be used.

[How]
The Extended Receiver Capability field shall check the
EXTENDED_RECEIVER_CAPABILITY_FIELD_PRESENT bit in the
TRAINING_AUX_RD_INTERVAL register.  Removed DPCD rev checking for VSC
SDP.

Signed-off-by: Derek Lai <Derek.Lai@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Tony Cheng <Tony.Cheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>