[NET]: Do not check netif_running() and carrier state in ->poll()

[NET]: Do not check netif_running() and carrier state in ->poll()

Drivers do this to try to break out of the ->poll()'ing loop
when the device is being brought administratively down.

Now that we have a napi_disable() "pending" state we are going
to solve that problem generically.

Signed-off-by: David S. Miller <davem@davemloft.net>