net: fec: Fix RMON registers on imx6

commit 38ae92d "fec: Add support for reading
RMON registers" causes the imx6Q to crash.

This fixes it by only enabling the RMON registers, the
registers are already cleared by the MAC being reset.

Signed-off-by: Jim Baxter <jim_baxter@mentor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fec_main.c

@@ -606,11 +606,8 @@ fec_restart(struct net_device *ndev, int duplex)
 		ecntl |= (1 << 4);
 
 #ifndef CONFIG_M5272
-	/* Disable, clear, and enable the MIB */
-	writel(1 << 31, fep->hwp + FEC_MIB_CTRLSTAT);
-	for (i = RMON_T_DROP; i < IEEE_R_OCTETS_OK; i++)
-		writel(0, fep->hwp + i);
-	writel(0, fep->hwp + FEC_MIB_CTRLSTAT);
+	/* Enable the MIB statistic event counters */
+	writel(0 << 31, fep->hwp + FEC_MIB_CTRLSTAT);
 #endif
 
 	/* And last, enable the transmit and receive processing */