net: ethernet: freescale: fs_enet: make mdiobb_ops const

Make this const as it is only stored in a const field of a
mdiobb_ctrl structure.
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fs_enet/mii-bitbang.c

@@ -100,7 +100,7 @@ static inline void mdc(struct mdiobb_ctrl *ctrl, int what)
 	in_be32(bitbang->dat);
 }
 
-static struct mdiobb_ops bb_ops = {
+static const struct mdiobb_ops bb_ops = {
 	.owner = THIS_MODULE,
 	.set_mdc = mdc,
 	.set_mdio_dir = mdio_dir,