drm/msm/dp: add connector functionality to configure HDR

Add connector function pointer to configure HDR setting as
per user-space. When user-space sets CONNECTOR_PROP_HDR_METADATA
property with HDR metadata for current HDR video stream,
call config_hdr to let the external interface configure the
hardware with HDR settings.

CRs-Fixed: 2157993
Change-Id: I83b560baadf237ab26cb003cdbc4f8b64b532432
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>