drivers: wifi: nxp: Fix embedded supplicant link mode issue.

1. When external stations connect to soft ap,
   Wi-Fi driver will send UAP_CLIENT_ASSOC event with data.
   nxp_wifi_wlan_event_callback will be called to process this event.
2. The data should include some basic station information
   but not only mac address of station.
3. Fill ap_sta_info with information of
   connected station but not soft ap self.
4. Fix: Wi-Fi driver send UAP_CLIENT_ASSOC event
   with basic station information.
5. Fix: ap_sta_info with information of connected station.

Signed-off-by: Qiankun Li <qiankun.li@nxp.com>