After system suspend, sometimes the r8169 doesn't work when ethernet
cable gets pluggued.

This issue happens because rtl_reset_work() doesn't get called from
rtl8169_runtime_resume(), after system suspend.

In rtl_task(), RTL_FLAG_TASK_* only gets cleared if this condition is
met:
if (!netif_running(dev) ||
    !test_bit(RTL_FLAG_TASK_ENABLED, tp->wk.flags))
    ...

If RTL_FLAG_TASK_ENABLED was cleared during system suspend while
RTL_FLAG_TASK_RESET_PENDING was set, the next rtl_schedule_task() won't
schedule task as the flag is still there.

So in addition to clearing RTL_FLAG_TASK_ENABLED, also clears other
flags.

Cc: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>