Allow 8021q device to be created in no-root network namespace
netpoll: Don't stop br_add_if because of netpoll.

Don't stop br_add_if and bonding if there are at least one
device support netpoll. Now even if br_netpoll_enable returns
error, we will go with success.

also, initilize np->dev_name so that we can print out the error
dev name if netpoll is not support.ed

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
kmsg_dump: enable kmsg_dump by default.

netoops is triggered by kmsg_dump. But now we don't output
anything in default. So this patch make default to be yes
so that we can trigger netoops in case of kernel panic.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>