dsa: mv88e6xxx: Fix error handling in mv88e6xxx_set_port_state

Return correct error code if _mv88e6xxx_reg_read returns an error.

Fixes: facd95b2e0ec0 ("net: dsa: mv88e6xxx: Add Hardware bridging support")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx.c

@@ -908,8 +908,10 @@ static int mv88e6xxx_set_port_state(struct dsa_switch *ds, int port, u8 state)
 	mutex_lock(&ps->smi_mutex);
 
 	reg = _mv88e6xxx_reg_read(ds, REG_PORT(port), PORT_CONTROL);
-	if (reg < 0)
+	if (reg < 0) {
+		ret = reg;
 		goto abort;
+	}
 
 	oldstate = reg & PORT_CONTROL_STATE_MASK;
 	if (oldstate != state) {