display: Change the place to set color mode

STC needs to pass the metadata of hdr layer, but
the metadata is not ready during the begining of
prepare. Change apply the color mode during the
begining of prepare and postpone passing the
metadata when it avaliable.

Change-Id: Ieea398022e18f6c5dbcd1aa3a29076bbf2e4bc9b
2 files changed