Add HAL APIs for TX power limits

To lower the instantaneous battery current draw of WiFi, we provide
a way to allow PowerManager to enable/disable Tx power limits.
In the legacy HAL, we call the API in Broadcom HAL to
enable/disable WiFi TX power limits.

Bug: 215193418
Test: New APIs work fine
Change-Id: I1fbe71c3380514e2eba96adc5902d2028a55e006
diff --git a/wifi/1.6/default/wifi_legacy_hal.cpp b/wifi/1.6/default/wifi_legacy_hal.cpp
index bb8cf59..2211897 100644
--- a/wifi/1.6/default/wifi_legacy_hal.cpp
+++ b/wifi/1.6/default/wifi_legacy_hal.cpp
@@ -1585,6 +1585,10 @@
     return status;
 }
 
+wifi_error WifiLegacyHal::enableWifiTxPowerLimits(const std::string& iface_name, bool enable) {
+    return global_func_table_.wifi_enable_tx_power_limits(getIfaceHandle(iface_name), enable);
+}
+
 void WifiLegacyHal::invalidate() {
     global_handle_ = nullptr;
     iface_name_to_handle_.clear();