driver/net/fec: support fixed speed connection

If MAC is directly connected to another MAC (like a switch for example)
we don't need to probe for a phy, autoneogation and so on. We simply
have to setup speed.

Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/drivers/net/fec_mxc.c b/drivers/net/fec_mxc.c
index 360f8e4..e871b3e 100644
--- a/drivers/net/fec_mxc.c
+++ b/drivers/net/fec_mxc.c
@@ -233,6 +233,7 @@
 	return ret;
 }
 
+#ifndef CONFIG_FEC_FIXED_SPEED
 static int miiphy_wait_aneg(struct eth_device *dev)
 {
 	uint32_t start;
@@ -260,6 +261,7 @@
 
 	return 0;
 }
+#endif /* CONFIG_FEC_FIXED_SPEED */
 #endif
 
 static int fec_rx_task_enable(struct fec_priv *fec)
@@ -502,6 +504,8 @@
 		}
 		speed = fec->phydev->speed;
 	}
+#elif CONFIG_FEC_FIXED_SPEED
+	speed = CONFIG_FEC_FIXED_SPEED;
 #else
 	miiphy_wait_aneg(edev);
 	speed = miiphy_speed(edev->name, fec->phy_id);