staging: brcm80211: bugfix for oops on firmware load problems

Upon firmware load failure, wl_release_fw() was called multiple
times. This caused the driver to oops. Solution was to remove redundant
wl_release_fw() calls.

Signed-off-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>