Add GSPI constants to libertas core.

Fix misleading comment in lbs_setup_firmware.
Signed-off-by: NColin McCabe <colin@cozybit.com>
Signed-off-by: NAndrey Yurovsky <andrey@cozybit.com>
Acked-by: NDan Williams <dcbw@redhat.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>