CVE-2026-68198: wifi: ath6kl: fix use-after-free in aggr_reset_state()

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

wifi: ath6kl: fix use-after-free in aggrresetstate()

The aggrresetstate() function uses timerdelete() (non-synchronous) for the aggregation timer before proceeding to delete TID state and before the structure is freed by callers like aggrmoduledestroy().

If the timer callback (aggrtimeout) is executing when aggrresetstate() is called, the callback will continue to access aggrconn fields like rxtid[] and stat[] which may be freed immediately after by kfree(aggrinfo->aggrconn) in aggrmoduledestroy().

Additionally, the timer callback can re-arm itself via modtimer() while aggrresetstate() is running, creating a more complex race condition.

Use timerdeletesync() instead to ensure any running timer callback has completed before returning.