Currently, RTS threshold is not handled for HT. Handle
user-specified threshold values for both aggregated
and unaggregated frames. Use the wiphy's threshold
parameter for now, it can be made per-VIF later on.
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>