libertas: pos[4] tested twice, 2nd should be pos[5]

pos[4] can't be both 0x43 and 0x04, 2nd should be pos[5]

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>