wifi: ath12k: Avoid memory leak while enabling statistics

In the Linux kernel, the following vulnerability has been resolved:

wifi: ath12k: Avoid memory leak while enabling statistics

Driver uses monitor destination rings for extended statistics mode and
standalone monitor mode. In extended statistics mode, TLVs are parsed from
the buffer received from the monitor destination ring and assigned to the
ppdu_info structure to update per-packet statistics. In standalone monitor
mode, along with per-packet statistics, the packet data (payload) is
captured, and the driver updates per MSDU to mac80211.

When the AP interface is enabled, only extended statistics mode is
activated. As part of enabling monitor rings for collecting statistics,
the driver subscribes to HAL_RX_MPDU_START TLV in the filter
configuration. This TLV is received from the monitor destination ring, and
kzalloc for the mon_mpdu object occurs, which is not freed, leading to a
memory leak. The kzalloc for the mon_mpdu object is only required while
enabling the standalone monitor interface. This causes a memory leak while
enabling extended statistics mode in the driver.

Fix this memory leak by removing the kzalloc for the mon_mpdu object in
the HAL_RX_MPDU_START TLV handling. Additionally, remove the standalone
monitor mode handlings in the HAL_MON_BUF_ADDR and HAL_RX_MSDU_END TLVs.
These TLV tags will be handled properly when enabling standalone monitor
mode in the future.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.3.1-00173-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3