Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/ieee802154/cc2520.c:221:5: warning:
 variable status set but not used [-Wunused-but-set-variable]

It is never used, so can be removed.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>