qca-wifi: Drop mgmt nbuf in tx_capture disabled case
If tx_capture is disabled, the frames notified to tx_capture
module needs to be freed.
This change frees mgmt frames in tx capture module, in case feature
is disabled
Change-Id: I71f102ba2f25f23bdcef63dddb525d5f7b0a692a
CRs-Fixed: 2643848