wifi: rtw89: mcc: handle the case where NoA start time has passed

MCC will limit the time a role can use in a schedule according to the
periodic NoA. Original logic didn't consider the case where NoA start
time has passed. It might lead to inaccurate result. So, tweak it.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250422014620.18421-9-pkshih@realtek.com