lan743x: Use correct MAC_CR configuration for 1 GBit speed

Corrected the MAC_CR configuration bits for 1 GBit operation. The data
sheet allows MAC_CR(2:1) to be 10 and also 11 for 1 GBit/s speed, but
only 10 works correctly.

Devices tested:
Microchip Lan7431, fixed-phy mode
Microchip Lan7430, normal phy mode

Fixes: 6f197fb6 ("lan743x: Added fixed link and RGMII support")
Signed-off-by: Roelof Berg <rberg@berg-solutions.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/microchip/lan743x_main.c

@@ -985,7 +985,7 @@ static void lan743x_phy_link_status_change(struct net_device *netdev)
 		break;
 		case SPEED_1000:
 			data |= MAC_CR_CFG_H_;
-			data |= MAC_CR_CFG_L_;
+			data &= ~MAC_CR_CFG_L_;
 		break;
 		}
 		lan743x_csr_write(adapter, MAC_CR, data);