drm/amd/display: clean up some formats and log

[why]
reduce az indirect register dump. need add az clock_gating control field
used in some project.

[how]
conditional output indrect register in the log.  add clock_gating feild

Reviewed-by: Sung joon Kim <Sungjoon.Kim@amd.com>
Acked-by: Anson Jacob <Anson.Jacob@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Charlene Liu <Charlene.Liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>