cxgb4: remove the name field from the adapter structure

Remove a field the driver uses to keep track of the name of the first
netdev it manages to register.  Do this by changing the registration
loop to stop the first time it fails so the first registered device is
trivial to tell.

Signed-off-by: Dimitris Michailidis <dm@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>