wifi: ath12k: fix inconsistent arvif state in vdev_create error paths

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

wifi: ath12k: fix inconsistent arvif state in vdev_create error paths

ath12k_mac_vdev_create() has three error path issues that leave arvif
in an inconsistent state:

1. When ath12k_wmi_vdev_create() fails, the function returns directly
without clearing arvif->ar, which was already set before the WMI
call. Subsequent code checking arvif->ar to determine vdev readiness
will see a non-NULL value despite no vdev existing in firmware.

2. When ath12k_wmi_send_peer_delete_cmd() fails in err_peer_del, the
code jumped to err: skipping the DP peer cleanup and vdev rollback,
leaving num_created_vdevs, vdev maps and arvif list membership live.

3. When ath12k_wait_for_peer_delete_done() fails, the code jumped to
err_vdev_del: skipping the DP peer cleanup.

Fix by changing the ath12k_wmi_vdev_create() failure to goto err instead
of returning directly, routing both err_peer_del failure paths through
err_dp_peer_del: for proper DP peer and vdev rollback, and consolidating
the arvif state cleanup at err:.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3