rtw88: update statistics to fw for fine-tuning performance

Since firmware can't have proper statistics, driver update the statistics
periodically to firmware to assist in tuning performance.

Signed-off-by: Po-Hao Huang <phhuang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210326092147.30252-1-pkshih@realtek.com