staging: wlan-ng: p80211wep.c: use lib/crc32

Use lib/crc32 instead of another implementation.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Link: https://lore.kernel.org/r/20191006140745.9952-1-thomas@m3y3r.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>