lenovo/x201: Fix dock recognition

Change-Id: I8b210786f660e2b2bae0d9ddd594386fd107cbe4
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/6706
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

src/mainboard/lenovo/x201/dock.c

@@ -67,5 +67,5 @@ int dock_present(void)
 	u16 gpiobase = pci_read_config16(PCH_LPC_DEV, GPIO_BASE) & 0xfffc;
 	u8 st = inb(gpiobase + 0x0c);
 
-	return !((st >> 3) & 1);
+	return ((st >> 3) & 7) != 7;
 }