net: sched: export __netdev_watchdog_up()

stable inclusion
from linux-4.19.131
commit 1a182e9c5f82fddf68c05ab00f0025f7613a64d3

--------------------------------

[ Upstream commit 1a3db27a ]

Since the quiesce/activate rework, __netdev_watchdog_up() is directly
called in the ucc_geth driver.

Unfortunately, this function is not available for modules and thus
ucc_geth cannot be built as a module anymore. Fix it by exporting
__netdev_watchdog_up().

Since the commit introducing the regression was backported to stable
branches, this one should ideally be as well.

Fixes: 79dde73c ("net/ethernet/freescale: rework quiesce/activate for ucc_geth")
Signed-off-by: NValentin Longchamp <valentin@longchamp.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NLi Aichun <liaichun@huawei.com>
Reviewed-by: Nguodeqing <geffrey.guo@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/sched/sch_generic.c

@@ -487,6 +487,7 @@ void __netdev_watchdog_up(struct net_device *dev)
 			dev_hold(dev);
 	}
 }
+EXPORT_SYMBOL_GPL(__netdev_watchdog_up);
 
 static void dev_watchdog_up(struct net_device *dev)
 {