For GFX context, the  ATC bit in SDMA*_GFX_VIRTUAL_ADDRESS  can be cleared
to perform in VM mode. For RLC context, to support ATC mode , ATC bit in
SDMA*_RLC*_VIRTUAL_ADDRESS should be set. SDMA_CNTL.ATC_L1_ENABLE bit is
global setting that enables the  L1-L2 translation for ATC address.
Signed-off-by: shaoyun liu <shaoyun.liu@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>