net: zynq_gem: Return error incase of invalid phy address

Return error from probe in case of invalid phy address.
This fixes the issue of uboot crash if phy is not detected.

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

drivers/net/zynq_gem.c

@@ -638,9 +638,7 @@ static int zynq_gem_probe(struct udevice *dev)
 	if (ret)
 		return ret;
 
-	zynq_phy_init(dev);
-
-	return 0;
+	return zynq_phy_init(dev);
 }
 
 static int zynq_gem_remove(struct udevice *dev)