drm/amd/display: Split arbiter programming for DCN42

drm/amd/display: Split arbiter programming for DCN42

[Why]
We don't want to update the timeout threshold for stall recovery in
firmware dynamically for DCN42 as we're not using FAMS.

Firmware should own programming of this register since the recovery
can be broken if driver updates the value to 0.

[How]
Split program_arbiter for dcn42 and skip the part that updates the
timeout threshold.

Reviewed-by: Leo Chen <leo.chen@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Signed-off-by: Chuanyu Tseng <Chuanyu.Tseng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>