netpoll: copy dev name of slaves to struct netpoll

Otherwise we will not see the name of the slave dev in error
message:

[  388.469446] (null):  doesn't support polling, aborting.

Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2 files changed