drm/amd/powerplay: update swSMU VCN/JPEG PG logics

Add lock protections and avoid unnecessary actions
if the PG state is already the same as required.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Tested-by: Matt Coffin <mcoffin13@gmail.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>