wifi: rtw89: introduce beacon tracking to improve connection stability

wifi: rtw89: introduce beacon tracking to improve connection stability

In ideal scenario, AP's beacon should transmit at the Target Beacon
Transmission Time (TBTT). However, in practice, beacon may be slightly
off-schedule. This beacon "drift" prevents the firmware from receiving
beacon at the expected TBTT, leading to connection disruptions.

To address this, we introduce beacon tracking mechanism to enhance overall
connection stability. This mechanism executes the following steps in each
cycle (2 seconds): 1) Based on the last 32 received beacons, compute the
minimum TBTT offset to use for the next cycle 2) Using the same 32 beacons,
calculate the drift of each. A histogram is plotted, and outliers are
identified using a boxplot. 3) According to the statistical results from
the second step, a maximum receive window size (beacon timeout) is selected
to cover approximately 80% of the beacons and applied to the next cycle.

Signed-off-by: Kuan-Chung Chen <damon.chen@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250811123744.15361-2-pkshih@realtek.com