bnxt_en: Implement missing tx timeout reset logic.

The reset logic calls bnxt_close_nic() and bnxt_open_nic() under rtnl_lock
from bnxt_sp_task.  BNXT_STATE_IN_SP_TASK must be cleared before calling
bnxt_close_nic() to avoid deadlock.

v2: Fixed white space error.  Thanks Dave.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>