wifi: ath12k: fix WMI TLV header misalignment

wifi: ath12k: fix WMI TLV header misalignment

When buf_len is not 4-byte aligned in ath12k_wmi_mgmt_send(), the
firmware asserts and triggers a recovery. The following error
messages are observed:

ath12k_pci 0004:01:00.0: failed to submit WMI_MGMT_TX_SEND_CMDID cmd
ath12k_pci 0004:01:00.0: failed to send mgmt frame: -108
ath12k_pci 0004:01:00.0: failed to tx mgmt frame, vdev_id 0 :-108
ath12k_pci 0004:01:00.0: waiting recovery start...

This issue was observed when running 'iw wlanx set power_save off/on'
in MLO station mode, which triggers the sending of an SMPS action frame
with a length of 27 bytes to the AP. To resolve the misalignment, use
buf_len_aligned instead of buf_len when constructing the WMI TLV header.

Tested-on: WCN7850 hw2.0 PCI WLAN.IOE_HMT.1.1-00011-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Signed-off-by: Miaoqing Pan <miaoqing.pan@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20250908015139.1301437-1-miaoqing.pan@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>