DC R9 285 HDMI audio regression since drm/amd/display: try to find matching audio inst for enc inst first

Submitted by Andy Furniss

Assigned to Default DRI bug account

Link to original bug (#104391)

Description

R9 285 Tonga with DC (only DC ever worked for HDMI audio with this card/TV combo)

Haven't tested any other use cases other than mine =

HDMI TV is off DVI-D monitor is on with X running, Turn on TV, do
xrandr --output HDMI-A-0 --auto && xrandr --output HDMI-A-0 --below DVI-D-0

Since this commit I get no sound.

commit cfb071f7a9673109415d097125b3c12c16836acc
Author: Charlene Liu charlene.liu@amd.com
Date: Wed Nov 15 18:55:57 2017 -0500

drm/amd/display: try to find matching audio inst for enc inst first

[Description]
in eDP+ HDMI/DP clone or extended configuration, audio inst changed from inst 1 to inst0.
No failure related this though, just playback device endpoint inst changed.
Also remove one addition register read.