qcacmn: Add extension2 data to radiotap header

There is a requirement to get sequence number and tid for tx
data packets in packet capture mode. These fields are not
received as part of WBM tx completion, but are obtained from
FW in ppdu stats. As WBM tx completion and FW ppdu stats are
two different events, the ppdu_stats of previously sent ppdu
are filled in the radiotap header of current tx ppdu in packet
capture mode.

Enhance code to add required fields such as ppdu_id of tx current
ppdu and ppdu_id, tid, start_seq, ba_bitmap of previously sent ppdu
as extension2 to radiotap header. These fields will be added in
radiotap header only when add_rtap_ext2 is set.

Change-Id: I448a9c03a770b61ab802d855bc5f1a6587bd01b3
CRs-Fixed: 3004472