agpgart: detected ALi M???? chipset with M1621

Add M1621 chipset name to ali-agp, preventing "Detected ALi M???? chipset"
message.
Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/char/agp/ali-agp.c

@@ -346,7 +346,7 @@ found:
 			devs[j].chipset_name = "M1641";
 			break;
 		case 0x43:
-			devs[j].chipset_name = "M????";
+			devs[j].chipset_name = "M1621";
 			break;
 		case 0x47:
 			devs[j].chipset_name = "M1647";