commonsys-intf: display: Fix ContentLightLevel max avg light lvl

- The field minPicAverageLightLevel is actually maxPicAverageLightLevel
  from the H.265 spec, mention it will be deprecated.
- Add new member maxPicAverageLightLevel which clients must use, this
  is same as maxFrameAverageLightLevel from CTA-861.G
- The unit for maxPicAverageLightLevel is 1 cd/m^2.

Change-Id: Ida73949d4e4595bc4505e7451c40c6e6976bd092
CRs-fixed: 2607978
1 file changed