Move setScanMode to legacy HAL

Cherry-pick from https://partner-android-review.git.corp.google.com/c/platform/hardware/interfaces/+/2369946
Implementation of setScanMode is platform-specific. It's more reasonable to move it the legacy HAL like other platform-specific APIs.

Bug: 265866990
Test: manual Test
Test: VTS
Change-Id: I2f8ff73b764ed1b9835b8e3157f673d7d558ae02
diff --git a/wifi/aidl/default/wifi_sta_iface.cpp b/wifi/aidl/default/wifi_sta_iface.cpp
index 08ed9d2..96dc809 100644
--- a/wifi/aidl/default/wifi_sta_iface.cpp
+++ b/wifi/aidl/default/wifi_sta_iface.cpp
@@ -561,9 +561,8 @@
 }
 
 ndk::ScopedAStatus WifiStaIface::setScanModeInternal(bool enable) {
-    // OEM's need to implement this on their devices if needed.
-    LOG(WARNING) << "setScanModeInternal(" << enable << ") not supported";
-    return createWifiStatus(WifiStatusCode::ERROR_NOT_SUPPORTED);
+    legacy_hal::wifi_error legacy_status = legacy_hal_.lock()->setScanMode(ifname_, enable);
+    return createWifiStatusFromLegacyError(legacy_status);
 }
 
 ndk::ScopedAStatus WifiStaIface::setDtimMultiplierInternal(const int multiplier) {