staging: mt7621-eth: Lock is never unlocked.

mtk_phy_link_adjust takes a spinlock and disables
interrupts, but never unlocks.
This can leave interrupts disabled on one CPU and
various things stop working.
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-eth/mdio.c

@@ -57,6 +57,7 @@ static void mtk_phy_link_adjust(struct net_device *dev)
 			}
 		}
 	}
+	spin_unlock_irqrestore(&eth->phy->lock, flags);
 }
 
 int mtk_connect_phy_node(struct mtk_eth *eth, struct mtk_mac *mac,