qcacmn: Fix FILS Discovery rx frames capture in packet capture mode

Currently the FILS Discovery rx frames are dropped in
tgt_mgmt_txrx_rx_frame_handler considering them as unspecified
packets as action category for FILS Discovery is not defined.

Define FILS Discovery action category so that the FILS Discovery
will not be considered as unspecified frames and dropped while
processing.

Change-Id: I72398caf3cbb1f7d53d5f97da9d1997af2b33595
CRs-Fixed: 3346195