USB: remove dbg() usage in USB networking drivers

The dbg() USB macro is so old, it predates me.  The USB networking drivers are
the last hold-out using this macro, and we want to get rid of it, so replace
the usage of it with the proper netdev_dbg() or dev_dbg() (depending on the
context) calls.

Some places we end up using a local variable for the debug call, so also
convert the other existing dev_* calls to use it as well, to save tiny amounts
of code space.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>