Based on the previous patch, make bridge support netpoll by:
1) implement the 2 methods to support netpoll for bridge;
2) modify netpoll during forwarding packets via bridge;
3) disable netpoll support of bridge when a netpoll-unabled device
is added to bridge;
4) enable netpoll support when all underlying devices support netpoll.
Cc: David Miller <davem@davemloft.net>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
c06ee961d3