[Why]
Screen corruption on Navi10 card

[How]
Set system context in DCN only on Renoir
Tested-by: NMatt Coffin <mcoffin13@gmail.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NYifan Zhang <yifan1.zhang@amd.com>
Reviewed-by: NRoman Li <Roman.Li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>