drm/amd/display: Remove unused local variables and function

Remove a couple of local variables that are only set but never used,
also remove an static utility function that is never used in consequence
of the variable removal.

This decrease the number of -Wunused-but-set-variable warnings.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Arthur Grillo <arthurgrillo@riseup.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/display: remove audio mute control in hpo dp

VPG doesn't have the ability to mute audio output by sending all 0s in
audio SDP. The existing implemention is disabling audio SDP instead.
This is same as what dp_audio_enable does. Since it is no longer
referenced by any callers, we decided to remove this interface for
simplicity.

Tested-by: Mark Broadworth <mark.broadworth@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/display: refactor enable/disable audio stream hw sequence

[why]
1. As recommended by hardware team, don't enable APG when stream is not
enabled.
2. Move audio stream encoder programming into link_hwss.

[how]
1. Merge dp_audio_enable into enable audio stream hw sequence.
2. Move stream encoder programming into link hwss level to unify stream
encoder programming interface.

Tested-by: Mark Broadworth <mark.broadworth@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/display: correct apg audio channel enable golden value

Hardware team has recommended to generically hard code this register to
0xFF as part of the effort to eventually remove this control. However
we set it to 0xF instead.
This causes 4 of audio 8ch to be muted.

Reviewed-by: Ariel Bernstein <eric.bernstein@amd.com>
Acked-by: Agustin Gutierrez Sanchez <agustin.gutierrez@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/display: Add DP 2.0 Audio Package Generator

HW Blocks:

+-----+
| HDA |
+-----+
|
|
HPO ===============|=============
| v
| +-----+
| | APG |
v +-----+

Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>