wifi: ath12k: fix out-of-bound access of qmi_invoke_handler()

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

wifi: ath12k: fix out-of-bound access of qmi_invoke_handler()

Currently, there is no terminator entry for ath12k_qmi_msg_handlers hence
facing below KASAN warning,

==================================================================
BUG: KASAN: global-out-of-bounds in qmi_invoke_handler+0xa4/0x148
Read of size 8 at addr ffffffd00a6428d8 by task kworker/u8:2/1273

CPU: 0 PID: 1273 Comm: kworker/u8:2 Not tainted 5.4.213 #0
Workqueue: qmi_msg_handler qmi_data_ready_work
Call trace:
dump_backtrace+0x0/0x20c
show_stack+0x14/0x1c
dump_stack+0xe0/0x138
print_address_description.isra.5+0x30/0x330
__kasan_report+0x16c/0x1bc
kasan_report+0xc/0x14
__asan_load8+0xa8/0xb0
qmi_invoke_handler+0xa4/0x148
qmi_handle_message+0x18c/0x1bc
qmi_data_ready_work+0x4ec/0x528
process_one_work+0x2c0/0x440
worker_thread+0x324/0x4b8
kthread+0x210/0x228
ret_from_fork+0x10/0x18

The address belongs to the variable:
ath12k_mac_mon_status_filter_default+0x4bd8/0xfffffffffffe2300 [ath12k]
[...]
==================================================================

Add a dummy terminator entry at the end to assist the qmi_invoke_handler()
in traversing up to the terminator entry without accessing an
out-of-boundary index.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1