wifi: ath12k: factor out peer assoc send-and-wait into a helper

wifi: ath12k: factor out peer assoc send-and-wait into a helper

ath12k_bss_assoc(), ath12k_mac_station_assoc() and
ath12k_sta_rc_update_wk() all open-code the same sequence: reinit the
peer_assoc_done completion, send the peer assoc WMI command, then wait
for the firmware confirmation event. The reinit_completion() was buried
in ath12k_peer_assoc_prepare(), far from the wait_for_completion_timeout()
that consumes it, making the reinit/send/wait sequence hard to follow,
and the three open-coded copies are easy to get out of sync.

Move the sequence into a new helper ath12k_mac_peer_assoc() and call it
from all three sites. The reinit, send and wait now live together so the
completion's lifecycle is easy to read.

While at it, ath12k_sta_rc_update_wk() previously warned but still
waited the full timeout when the peer assoc command failed to send. Now
a send failure returns immediately and skips the pointless 1 second
wait, matching the other two callers.

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

Signed-off-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Reviewed-by: Rameshkumar Sundaram <rameshkumar.sundaram@oss.qualcomm.com>
Link: https://patch.msgid.link/20260720-ath12k-fw-allocated-ml-peer-id-v2-2-630632758a80@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>