drm/amdgpu: use VCN firmware offset for cache window

Since we are using the signed FW now, and also using PSP firmware loading,
but it's still potential to break driver when loading FW directly
instead of PSP, so we should add offset.
Signed-off-by: Leo Liu <leo.liu@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c

@@ -372,11 +372,8 @@ static void vcn_v2_0_mc_resume(struct amdgpu_device *adev)
 		WREG32_SOC15(UVD, 0, mmUVD_LMI_VCPU_CACHE_64BIT_BAR_HIGH,
 			upper_32_bits(adev->vcn.gpu_addr));
 		offset = size;
-		/* No signed header for now from firmware
 		WREG32_SOC15(UVD, 0, mmUVD_VCPU_CACHE_OFFSET0,
 			AMDGPU_UVD_FIRMWARE_OFFSET >> 3);
-		*/
-		WREG32_SOC15(UVD, 0, mmUVD_VCPU_CACHE_OFFSET0, 0);
 	}
 
 	WREG32_SOC15(UVD, 0, mmUVD_VCPU_CACHE_SIZE0, size);