staging: brcm80211: replace hndcrc16 with crc-ccitt function

The implementation of hndcrc16 is identical to that of the crc-ccitt
function available in linux kernel library functions. The driver now
uses the crc-ccitt function.

Cc: devel@linuxdriverproject.org
Cc: linux-wireless@vger.kernel.org
Cc: Brett Rudley <brudley@broadcom.com>
Cc: Henry Ptasinski <henryp@broadcom.com>
Cc: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>