drivers/net: use tasklet_kill in device remove/close process

drivers/net: use tasklet_kill in device remove/close process

Some driver uses tasklet_disable in device remove/close process,
tasklet_disable will inc tasklet->count and return. If the tasklet
is not handled yet because some softirq pressure, the tasklet will
placed on the tasklet_vec, never have a chance to excute. This might
lead to ksoftirqd heavy loaded, wakeup with pending_softirq, but
tasklet is disabled. tasklet_kill should be used in this case.

Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>