staging: r8188eu: remove unused enum from ieee80211.h.

Remove unused enum from ieee80211.h.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210903093354.12645-4-straube.linux@gmail.com


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