staging: rtl8723au: core: rtw_recv: remove useless codes

There are some useless codes in rtw_free_recvframe23a_queue() and
recvframe_defrag(), so remove them.

Signed-off-by: Geliang Tang <geliangtang@163.com>
Acked-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>