drm/amd/display: Fix check for setting input TF

drm/amd/display: Fix check for setting input TF

We no longer change the plane state pointer for full updates, and as
such, we weren't setting the input transfer function and programming the
degamma registers when we are supposed to. Check for a full update, an
input TF change, or a gamma change in the update flags instead to correct
this.

Signed-off-by: Andrew Jiang <Andrew.Jiang@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>