1) implement the 2 methods to support netpoll for bonding;
2) modify netpoll during forwarding packets via bonding;
3) disable netpoll support of bonding when a netpoll-unabled device
is added to bonding;
4) enable netpoll support when all underlying devices support netpoll.
Cc: Andy Gospodarek <gospo@redhat.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Jay Vosburgh <fubar@us.ibm.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: WANG Cong <amwang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>