drm/amd/pm: Revert state if force level fails

Before forcing level, CG/PG is disabled or enabled depending on the new
level. However if the force level operation fails, CG/PG state remains
modified. Revert the state change on failure. Also, move invalid
operation checks to the beginning before any logic that could change SOC
state.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>