netdev: smsc911x: allow building on Blackfin systems

The smsc911x driver works fine on Blackfin systems, so add it to the arch
list in the Kconfig.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 3df8fc4..f19018d 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -1001,7 +1001,7 @@
 
 config SMSC911X
 	tristate "SMSC LAN911x/LAN921x families embedded ethernet support"
-	depends on ARM || SUPERH
+	depends on ARM || SUPERH || BLACKFIN
 	select CRC32
 	select MII
 	select PHYLIB