wpa_supplicant_lib: Send channel update event for 'country' command

Change-Id: I488c6deb6472cc9f0e8ed723d4b7fd332adf34ed
wpa_driver_nl80211_driver_cmd: ignore certain commands

  - ignore (pretend success) these commands:
     COUNTRY, SETBAND, BTCOEXSCAN-START, BTCOEXSCAN-STOP

Change-Id: Icd5376b0a9368a185b03883d2be205f471ce6bee