wifi: rtw89: rtw8852b{t}: fix TSSI debug timestamps

Since the vendor driver is claimed to measure 'tssi_alimk_time' of
'struct rtw89_tssi_info' in microseconds, adjust rtw8852b{t}-specific
'_tssi_alimentk()' to not mess the former with nanoseconds and print
both per-call and accumulated times. Compile tested only.

Fixes: 7f18a70d ("wifi: rtw89: 8852b: rfk: add TSSI")
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250213095006.1308810-1-dmantipov@yandex.ru