drm/amd/display: allow hpo and dio encoder switching during dp retrain test

[why]
During DP2.1 LL CTS if test equipment requests to change between
DP2.1 and DP1.4 link rates, we need to swap between HPO and DIO
encoders by remapping encoder resource.

[how]
Add a function dc resource to update encoder resources and toggle
dpms state for all enabled stream associated witht the link under test.

Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>