Some RNDIS devices don't respond on the control channel until polled
on the status channel.  In particular, this was reported to be the
case for the 2Wire HomePortal 1000SW.

This is roughly based on a patch by John Carr <john.carr@unrouted.co.uk>
which is reported to be needed for use with some Windows Mobile devices
and which is currently applied by Mandriva.
Reported-by: Mark Glassberg <vzeeaxwl@myfairpoint.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Tested-by: Mark Glassberg <vzeeaxwl@myfairpoint.net>
Signed-off-by: David S. Miller <davem@davemloft.net>