net: fec: Adjust ENET MDIO timeouts

On extensive NFS boots on a mx6qsabrelite board it was noted that "FEC: MDIO read timeout" were occuring,
which caused failure on loading the FEC driver.

The original FEC_MII_TIMEOUT was set to 1 ms, which is too low when passed to the usecs_to_jiffies macro.

On ARM one jiffy is 10ms, so use a timeout of 30ms, which corresponds to 3 jiffies.

After running extensive NFS boots, the MDIO timeouts do not occur anymore with this change.
Signed-off-by: NRogerio Pimentel <rogerio.pimentel@freescale.com>
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fec.c

@@ -255,7 +255,7 @@ struct fec_enet_private {
 #define FEC_MMFR_TA		(2 << 16)
 #define FEC_MMFR_DATA(v)	(v & 0xffff)
 
-#define FEC_MII_TIMEOUT		1000 /* us */
+#define FEC_MII_TIMEOUT		30000 /* us */
 
 /* Transmitter timeout */
 #define TX_TIMEOUT (2 * HZ)