Fixing compiler warnings

Adjusting toolchain files which compiler warnings to enable.

Fixing compiler warnings reported by Arm Clang and Arm GCC.

Change-Id: I715e875904ffd7ecfe994d3093cdf066373981b1
diff --git a/applications/message_handler/message_handler.cpp b/applications/message_handler/message_handler.cpp
index 7401546..f9f7304 100644
--- a/applications/message_handler/message_handler.cpp
+++ b/applications/message_handler/message_handler.cpp
@@ -375,7 +375,7 @@
 }
 
 void OutgoingMessageHandler::readCapabilties(ethosu_core_msg_capabilities_rsp &rsp) {
-    rsp = {0};
+    rsp = {};
 
 #ifdef ETHOSU
     struct ethosu_driver_version version;