net/fec: fix MMFR_OP type in fec_enet_mdio_write

FEC_MMFR_OP_WRITE should be used than FEC_MMFR_OP_READ in
a mdio write operation.

It's probably a typo introduced by commit:

e6b043d512fa8d9a3801bf5d72bfa3b8fc3b3cc8
netdev/fec.c: add phylib supporting to enable carrier detection (v2)

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/fec.c

@@ -651,8 +651,8 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 	fep->mii_timeout = 0;
 	init_completion(&fep->mdio_done);
 
-	/* start a read op */
-	writel(FEC_MMFR_ST | FEC_MMFR_OP_READ |
+	/* start a write op */
+	writel(FEC_MMFR_ST | FEC_MMFR_OP_WRITE |
 		FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(regnum) |
 		FEC_MMFR_TA | FEC_MMFR_DATA(value),
 		fep->hwp + FEC_MII_DATA);