mac80211: move fragment flag to info flag as dont-fragment
The purpose of this is two-fold:
1) by moving it out of tx_data.flags, we can in
another patch move the radiotap parsing so it
no longer is in the hotpath
2) if a device implements fragmentation but can
optionally skip it, the radiotap request for
not doing fragmentation may be honoured
Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>