mac80211: add radiotap flag to prevent sequence number overwrite

The radiotap specification contains a flag to indicate that the sequence
number of an injected frame should not be overwritten. Parse this flag
and define and set a corresponding Tx control flag.

Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@kuleuven.be>
Link: https://lore.kernel.org/r/20200723100153.31631-2-Mathy.Vanhoef@kuleuven.be


Signed-off-by: Johannes Berg <johannes.berg@intel.com>