fix compilation of intel/sch northbridge code with gcc 4.6

Change-Id: I57804dff9e37f0127900ebb7a67118382944eb89
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/264
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/northbridge/intel/sch/raminit.c

@@ -70,6 +70,9 @@ static u32 detect_softstrap_base(void)
 	case 4:
 		base_addr = 0xFFFE0000;
 		break;
+	default:
+		base_addr = 0;
+		die("No valid softstrap base found.\n");
 	}
 	return base_addr;
 }