staging: rtl8723au: Get rid of duplicate ieee80211 frame_control defines

This is all defined nicely in ieee80211.h, this was all duplication
serving no other purpose than to obfuscate the code.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>