Modified frequency changed event to framework

Removed the logic to send frequency
changed event to framework, on receiving
WPA_BSS_FREQ_CHANGED_FLAG attribute change.
This is because, this event is specific to
STA side functionality. Added a new frequency
changed notification handler. Send the new
frequency to framework from this handler.

Bug: 233074707
Test: Manual - Established P2P connection & confirmed from logs
      that channel change event is received correctly on
      framework side(used wpa_cli -i<ifname>
      chan_switch 10 2412 0 2412 2412 to trigger channel switch)
Change-Id: I75d3c9ad3ab357ee0d8d9e58bf38870bb3a21e98
diff --git a/wpa_supplicant/notify.h b/wpa_supplicant/notify.h
index f700017..996be84 100644
--- a/wpa_supplicant/notify.h
+++ b/wpa_supplicant/notify.h
@@ -217,5 +217,6 @@
 void wpas_notify_qos_policy_reset(struct wpa_supplicant *wpa_s);
 void wpas_notify_qos_policy_request(struct wpa_supplicant *wpa_s,
 		struct dscp_policy_data *policies, int num_policies);
+void wpas_notify_frequency_changed(struct wpa_supplicant *wpa_s, int frequency);
 
 #endif /* NOTIFY_H */