drm/amdgpu: allow fragment processing for invalid PTEs

That should improve the PRT performance on Vega quite a bit.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Acked-by: Junwei Zhang <Jerry.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1552,7 +1552,7 @@ static void amdgpu_vm_fragment(struct amdgpu_pte_update_params *params,
 		max_frag = 31;
 
 	/* system pages are non continuously */
-	if (params->src || !(flags & AMDGPU_PTE_VALID)) {
+	if (params->src) {
 		*frag = 0;
 		*frag_end = end;
 		return;