drm/amd/display: Remove otg w/a toggling on HPO interfaces

[why&how]
Adjust otg w/a disable condition to include HPO explicitly rather than
assuming it is implicitly used through DP2.

Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Signed-off-by: Ausef Yousof <Ausef.Yousof@amd.com>
Signed-off-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>