[TG3]: Clear GPIO mask before storing.

The GPIO settings may change during reset and so the stored values in
tp->grc_local_ctrl should be cleared first.
Signed-off-by: Gary Zambrano <zambrano@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -6454,6 +6454,7 @@ static int tg3_reset_hw(struct tg3 *tp, int reset_phy)
 		if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5755)
 			gpio_mask |= GRC_LCLCTRL_GPIO_UART_SEL;
 
+		tp->grc_local_ctrl &= ~gpio_mask;
 		tp->grc_local_ctrl |= tr32(GRC_LOCAL_CTRL) & gpio_mask;
 
 		/* GPIO1 must be driven high for eeprom write protect */