drm/nouveau/kms: don't fail if there's no dcb table entries

Fixes module not loading on Tesla K20.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_bios.c

@@ -1878,9 +1878,6 @@ parse_dcb_table(struct drm_device *dev, struct nvbios *bios)
 	if (dcb->version < 0x21)
 		merge_like_dcb_entries(dev, dcb);
 
-	if (!dcb->entries)
-		return -ENXIO;
-
 	/* dump connector table entries to log, if any exist */
 	idx = -1;
 	while ((conn = olddcb_conn(dev, ++idx))) {

drivers/gpu/drm/nouveau/nouveau_display.c

@@ -332,10 +332,15 @@ nouveau_display_create(struct drm_device *dev)
 
 	if (nouveau_modeset == 1 ||
 	    (nouveau_modeset < 0 && pclass == PCI_CLASS_DISPLAY_VGA)) {
+		if (drm->vbios.dcb.entries) {
 			if (nv_device(drm->device)->card_type < NV_50)
 				ret = nv04_display_create(dev);
 			else
 				ret = nv50_display_create(dev);
+		} else {
+			ret = 0;
+		}
+
 		if (ret)
 			goto disp_create_err;