drm/amdgpu/gmc9: remove dummy read workaround for newer chips

Aldebaran has a hw fix so no longer requires the workaround.

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c

@@ -574,7 +574,8 @@ static int gmc_v9_0_process_interrupt(struct amdgpu_device *adev,
 	 * be updated to avoid reading an incorrect value due to
 	 * the new fast GRBM interface.
 	 */
-	if (entry->vmid_src == AMDGPU_GFXHUB_0)
+	if ((entry->vmid_src == AMDGPU_GFXHUB_0) &&
+	    (adev->asic_type < CHIP_ALDEBARAN))
 		RREG32(hub->vm_l2_pro_fault_status);
 
 	status = RREG32(hub->vm_l2_pro_fault_status);
@@ -802,7 +803,8 @@ static void gmc_v9_0_flush_gpu_tlb(struct amdgpu_device *adev, uint32_t vmid,
 		 * be cleared to avoid a false ACK due to the new fast
 		 * GRBM interface.
 		 */
-		if (vmhub == AMDGPU_GFXHUB_0)
+		if ((vmhub == AMDGPU_GFXHUB_0) &&
+		    (adev->asic_type < CHIP_ALDEBARAN))
 			RREG32_NO_KIQ(hub->vm_inv_eng0_req +
 				      hub->eng_distance * eng);