drivers: net: fsl_enetc_mdio: return with time-out if HW is stuck

On some boards MDIO may get stuck if it detects echo on the line.  This is
a know hardware issue, there is a board fix for it.  In case we're running
on a board that doesn't have the fix, we don't want to loop here forever
and freeze U-Boot.

Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/drivers/net/fsl_enetc_mdio.c b/drivers/net/fsl_enetc_mdio.c
index b4463a5..47257a6 100644
--- a/drivers/net/fsl_enetc_mdio.c
+++ b/drivers/net/fsl_enetc_mdio.c
@@ -17,8 +17,13 @@
 
 static void enetc_mdio_wait_bsy(struct enetc_mdio_priv *priv)
 {
-	while (enetc_read(priv, ENETC_MDIO_CFG) & ENETC_EMDIO_CFG_BSY)
+	int to = 10000;
+
+	while ((enetc_read(priv, ENETC_MDIO_CFG) & ENETC_EMDIO_CFG_BSY) &&
+	       --to)
 		cpu_relax();
+	if (!to)
+		printf("T");
 }
 
 int enetc_mdio_read_priv(struct enetc_mdio_priv *priv, int addr, int devad,