sdm: Add DISPLAY_BT2020 color mode

For pluggable displays report DISPLAY_BT2020 color mode if the
panel is hdr, DISPLAY_BT2020 is BT2020 + SRGB and change gamma
transfer from Transfer_Gamma2_2 to Transfer_sRGB for BT2020.

CRs-Fixed: 2450712
Change-Id: I91ae0d35f2d0688e1c7020def4da757c0b45d1a5
5 files changed