drm/nvc0/gr: fix mthd data submission

If the initial data element is 0, it will never be written, even
though the value from the previous method may be there.

Signed-off-by: Kelly Doran <kel.p.doran@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/engine/graph/nvc0.c

@@ -334,7 +334,7 @@ nvc0_graph_mthd(struct nvc0_graph_priv *priv, struct nvc0_graph_mthd *mthds)
 	while ((mthd = &mthds[i++]) && (init = mthd->init)) {
 		u32  addr = 0x80000000 | mthd->oclass;
 		for (data = 0; init->count; init++) {
-			if (data != init->data) {
+			if (init == mthd->init || data != init->data) {
 				nv_wr32(priv, 0x40448c, init->data);
 				data = init->data;
 			}