drm/amd/display: Make DCN35 OTG disable w/a reusable

drm/amd/display: Make DCN35 OTG disable w/a reusable

The logic for the OTG disable workaround is particularly complex and
should be leveraged going forward instead of reimplementing and
maintaining it for multiple ASIC.

Reviewed-by: Ovidiu Bunea <ovidiu.bunea@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>