wifi: ath12k: Fix the assignment of logical link index

wifi: ath12k: Fix the assignment of logical link index

Per-link logical index is assigned from the global counter,
ahsta->num_peer. This logical index is sent to firmware during peer
association. If there is a failure in creating a link station,
ath12k_mac_free_unassign_link_sta() clears the link, but does not decrement
the logical link index. This will result in a higher logical link index for
the next link station created. Also, if there is a leak in logical link
index as we assign the incremented num_peer, then the index can exceed the
maximum valid value of 15.

As an example, let's say we have a 2 GHz + 5 GHz + 6 GHz MLO setup. So the
logical link indices that they have are 0, 1 and 2, respectively. If the
5 GHz link is removed, logical link index 1 becomes available, and num_peer
is not reduced to 2 and still remains at 3. If a new 5 GHz link is added
later, it gets the index 3, instead of reusing link index 1. Also,
num_peer is increased to 4, though only 3 links are present.

To resolve these, create a bitmap, free_logical_link_idx, that tracks the
available logical link indices. When a link station is created, select the
first free logical index and when a link station is removed, mark its
logical link index as available by setting the bit.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.6-01181-QCAHKSWPL_SILICONZ-1

Signed-off-by: Manish Dharanenthiran <manish.dharanenthiran@oss.qualcomm.com>
Signed-off-by: Roopni Devanathan <roopni.devanathan@oss.qualcomm.com>
Reviewed-by: Rameshkumar Sundaram <rameshkumar.sundaram@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20260226041911.2434999-1-roopni.devanathan@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>