qcacld-3.0: Set nbuf to NULL in error handling of wma_tx_packet

The caller of wma_tx_packet does not need to check if nbuf becomes
to NULL to decide if the nbuf free is needed. It is the designing
job of wma_tx_packet to free it if there is something wrong. Fix
one of the double free issue in ADDBA response transmission.

CRs-Fixed: 2379912
Change-Id: I944dea72a72cf9d937a72a3e0a31bbad88c8694d
1 file changed