staging: brcm80211: Fix handling of firmware and inits on big-endian platforms

The firmware files are encoded as little-endian.  Do the appropriate swapping
for big-endian platforms.

Tested on Mac G5 PPC and BCM63281.

Signed-off-by: Henry Ptasinski <henryp@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Tested-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>