net/bfin_mac.c MDIO namespace fixes

Commit 2e888103


(phylib: add mdiobus_{read,write}) causes the
following compile error:

<--  snip  -->

...
  CC      drivers/net/bfin_mac.o
drivers/net/bfin_mac.c:272: error: conflicting types for 'mdiobus_read'
include/linux/phy.h:130: error: previous declaration of 'mdiobus_read' was here
drivers/net/bfin_mac.c:287: error: conflicting types for 'mdiobus_write'
include/linux/phy.h:131: error: previous declaration of 'mdiobus_write' was here
make[3]: *** [drivers/net/bfin_mac.o] Error 1

<--  snip  -->

This patch prefixes the driver functions with bfin_

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>