ethernet: Remove redundant statement

The variable will be assigned again later in the if condition,
there is no meaning there.

drivers/net/ethernet/broadcom/tg3.c:5750:2 warning:

Value stored to 'current_link_up' is never read.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: luo penghao <luo.penghao@zte.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/tg3.c

@@ -5747,7 +5747,6 @@ static int tg3_setup_fiber_phy(struct tg3 *tp, bool force_reset)
 	tw32_f(MAC_EVENT, MAC_EVENT_LNKSTATE_CHANGED);
 	udelay(40);
 
-	current_link_up = false;
 	tp->link_config.rmt_adv = 0;
 	mac_status = tr32(MAC_STATUS);