wifi: Duplicate getValidChannelsForBand in AP iface

This functionality is needed even for AP iface. So, duplicate this
method.

Changes in the CL:
1. Add getValidChannelsForBand() in IWifiApIface.
2. Rename StaBackgroundScanBan to WifiBand to make it a more generic
name.
3. Change the existing method name in IWifiStaIface to match with the
one in IWifiApIface.

While there,
Fix indentation in hidl_callback_util.h

Bug: 35663149
Test: Compiles
Change-Id: Iaeb6c323e13eedf2f98de92fea77e327c76ffa5b
diff --git a/wifi/1.0/default/wifi_sta_iface.cpp b/wifi/1.0/default/wifi_sta_iface.cpp
index 55c9cf7..0c84102 100644
--- a/wifi/1.0/default/wifi_sta_iface.cpp
+++ b/wifi/1.0/default/wifi_sta_iface.cpp
@@ -106,15 +106,13 @@
                          hidl_status_cb);
 }
 
-Return<void> WifiStaIface::getValidFrequenciesForBackgroundScan(
-    StaBackgroundScanBand band,
-    getValidFrequenciesForBackgroundScan_cb hidl_status_cb) {
-  return validateAndCall(
-      this,
-      WifiStatusCode::ERROR_WIFI_IFACE_INVALID,
-      &WifiStaIface::getValidFrequenciesForBackgroundScanInternal,
-      hidl_status_cb,
-      band);
+Return<void> WifiStaIface::getValidFrequenciesForBand(
+    WifiBand band, getValidFrequenciesForBand_cb hidl_status_cb) {
+  return validateAndCall(this,
+                         WifiStatusCode::ERROR_WIFI_IFACE_INVALID,
+                         &WifiStaIface::getValidFrequenciesForBandInternal,
+                         hidl_status_cb,
+                         band);
 }
 
 Return<void> WifiStaIface::startBackgroundScan(
@@ -363,14 +361,13 @@
 }
 
 std::pair<WifiStatus, std::vector<WifiChannelInMhz>>
-WifiStaIface::getValidFrequenciesForBackgroundScanInternal(
-    StaBackgroundScanBand band) {
+WifiStaIface::getValidFrequenciesForBandInternal(WifiBand band) {
   static_assert(sizeof(WifiChannelInMhz) == sizeof(uint32_t), "Size mismatch");
   legacy_hal::wifi_error legacy_status;
   std::vector<uint32_t> valid_frequencies;
   std::tie(legacy_status, valid_frequencies) =
-      legacy_hal_.lock()->getValidFrequenciesForGscan(
-          hidl_struct_util::convertHidlGscanBandToLegacy(band));
+      legacy_hal_.lock()->getValidFrequenciesForBand(
+          hidl_struct_util::convertHidlWifiBandToLegacy(band));
   return {createWifiStatusFromLegacyError(legacy_status), valid_frequencies};
 }