wifi: Add method implementations in IWifiStaIface

Hookup the legacy HAL functions to the corresponding HIDL methods in
WifiStaIface and perform the necessary struct conversions.

Bug: 31991459
Test: Compiles
Change-Id: I8c0b9be2e375dd7147408e41a88de3f1c6f98d08
diff --git a/wifi/1.0/default/wifi_sta_iface.h b/wifi/1.0/default/wifi_sta_iface.h
index 09a883c..cdfe951 100644
--- a/wifi/1.0/default/wifi_sta_iface.h
+++ b/wifi/1.0/default/wifi_sta_iface.h
@@ -39,6 +39,7 @@
   // Refer to |WifiChip::invalidate()|.
   void invalidate();
   bool isValid();
+  std::vector<sp<IWifiStaIfaceEventCallback>> getEventCallbacks();
 
   // HIDL methods exposed.
   Return<void> getName(getName_cb hidl_status_cb) override;