Net: macb: reset GBE bit when fallback checking

If the GBE bit is set, when do next time autonegotiation,
if the result is not 1000Mbps, it will fallback to 100Mbps
checking. So, we need to clear the GBE bit.

Signed-off-by: Bo Shen <voice.shen@atmel.com>

drivers/net/macb.c

@@ -515,7 +515,7 @@ static int macb_phy_init(struct macb_device *macb)
 	       lpa);
 
 	ncfgr = macb_readl(macb, NCFGR);
-	ncfgr &= ~(MACB_BIT(SPD) | MACB_BIT(FD));
+	ncfgr &= ~(MACB_BIT(SPD) | MACB_BIT(FD) | GEM_BIT(GBE));
 	if (speed)
 		ncfgr |= MACB_BIT(SPD);
 	if (duplex)