drm/amd/display: Update FAMS2 config cmd

drm/amd/display: Update FAMS2 config cmd

The FAMS2 stream and sub-state have been separated into
2 different commands. Update the cmd function to send
one command each for the stream and sub-state.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Dillon Varone <dillon.varone@amd.com>
Signed-off-by: Alvin Lee <Alvin.Lee2@amd.com>
Signed-off-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>