arch: powerpc: mpc85xx: free MDIO bus if mdio_register fails

If mdio_register fails, it is nice to not leave behind dangling
allocated memory.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
diff --git a/arch/powerpc/cpu/mpc85xx/ether_fcc.c b/arch/powerpc/cpu/mpc85xx/ether_fcc.c
index 1f6f557..5cf0a3f 100644
--- a/arch/powerpc/cpu/mpc85xx/ether_fcc.c
+++ b/arch/powerpc/cpu/mpc85xx/ether_fcc.c
@@ -449,8 +449,10 @@
 		mdiodev->write = bb_miiphy_write;
 
 		retval = mdio_register(mdiodev);
-		if (retval < 0)
+		if (retval < 0) {
+			mdio_free(mdiodev);
 			return retval;
+		}
 #endif
 	}