Wifi: Support check on device capability for 6GHZ

This commit adds the HAL APIs and implementation to support checking
whether device supports 6GHz band or not.
VTS test has been added for the new api.

Bug: 139354972
Test: Manual: Make sure capability is read correctly.
Test: VTS test.
Change-Id: I03b0c6017666ffd3663d5979d6e6a2bd93043c48
diff --git a/wifi/1.4/default/wifi_legacy_hal.cpp b/wifi/1.4/default/wifi_legacy_hal.cpp
index 8139253..ae3c447 100644
--- a/wifi/1.4/default/wifi_legacy_hal.cpp
+++ b/wifi/1.4/default/wifi_legacy_hal.cpp
@@ -479,7 +479,7 @@
 std::pair<wifi_error, uint32_t> WifiLegacyHal::getSupportedFeatureSet(
     const std::string& iface_name) {
     feature_set set;
-    static_assert(sizeof(set) == sizeof(uint32_t),
+    static_assert(sizeof(set) == sizeof(uint64_t),
                   "Some feature_flags can not be represented in output");
     wifi_error status = global_func_table_.wifi_get_supported_feature_set(
         getIfaceHandle(iface_name), &set);