CVE-2026-68199: wifi: ath6kl: fix OOB access from firmware ADDBA window size

In the Linux kernel, the following vulnerability has been resolved: wifi: ath6kl: fix OOB access from firmware ADDBA window size aggr_recv_addba_req_evt() logs a debug message when the firmware-supplied win_sz is outside [AGGR_WIN_SZ_MIN, AGGR_WIN_SZ_MAX] but does not return. The out-of-range win_sz is then used in TID_WINDOW_SZ() to compute a kzalloc size and stored in rxtid->hold_q_sz, leading to zero-size or overflowed allocations and subsequent out-of-bounds access. Clean up any previously active aggregation session for the TID first, then return early when win_sz is out of the valid range, instead of proceeding with a broken allocation size.