drm/nouveau/gpio: place upper limit on using old-school tvdac bios data

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/subdev/bios/gpio.c

@@ -101,8 +101,8 @@ dcb_gpio_parse(struct nouveau_bios *bios, int idx, u8 func, u8 line,
 	}
 
 	/* DCB 2.2, fixed TVDAC GPIO data */
-	if ((entry = dcb_table(bios, &ver, &hdr, &cnt, &len)) && ver >= 0x22) {
-		if (func == DCB_GPIO_TVDAC0) {
+	if ((entry = dcb_table(bios, &ver, &hdr, &cnt, &len))) {
+		if (ver >= 0x22 && ver < 0x30 && func == DCB_GPIO_TVDAC0) {
 			u8 conf = nv_ro08(bios, entry - 5);
 			u8 addr = nv_ro08(bios, entry - 4);
 			if (conf & 0x01) {