net: dsa: b53: relax is63xx() condition

BCM63xx switches are present on bcm63xx and bmips devices.
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/b53/b53_priv.h

@@ -186,11 +186,7 @@ static inline int is531x5(struct b53_device *dev)
 
 static inline int is63xx(struct b53_device *dev)
 {
-#ifdef CONFIG_BCM63XX
 	return dev->chip_id == BCM63XX_DEVICE_ID;
-#else
-	return 0;
-#endif
 }
 
 static inline int is5301x(struct b53_device *dev)