wifi: ath12k: Decrease ath12k_mac_station_assoc() stack usage

wifi: ath12k: Decrease ath12k_mac_station_assoc() stack usage

Building the ath12k driver with llvm-18.1.7-x86_64 produces the warning:

drivers/net/wireless/ath/ath12k/mac.c:5606:12: warning: stack frame size (1176) exceeds limit (1024) in 'ath12k_mac_op_sta_state' [-Wframe-larger-than]

ath12k_mac_op_sta_state() itself does not consume much stack, but it
calls ath12k_mac_handle_link_sta_state() which in turn calls
ath12k_mac_station_add(). Since those are both static functions with
only one caller, it is suspected that these both get inlined, and
their stack usage is reported for ath12k_mac_op_sta_state().

A major contributor to the ath12k_mac_station_assoc() stack usage is:

	struct ath12k_wmi_peer_assoc_arg peer_arg;

Avoid the excess stack usage by dynamically allocating peer_arg
instead of declaring it on the stack.

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

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://patch.msgid.link/20241217202618.1329312-5-kvalo@kernel.org
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>