[PATCH] libertas: let get nick return what set nick has set

Make the get-nickname wireless extension actually work. Before
this patch, I could do "iwconfig eth1 nick BLAH" but "iwconfig
eth1" would have still showed "MRVL-USB8388" to me. Hey, and that
was wrong anyway, I'm on a CF card, not on USB :-)

Signed-off-by: Holger Schurig <hs4233@mail.mn-solutions.de>
Acked-By: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>