Add MUL (vector by element), fix FCVTN, make svcs use MakeError too

Ryujinx.Core/OsHle/ErrorCode.cs

@@ -0,0 +1,10 @@
+namespace Ryujinx.Core.OsHle
+{
+    static class ErrorCode
+    {
+        public static uint MakeError(ErrorModule Module, int Code)
+        {
+            return (uint)Module | ((uint)Code << 9);
+        }
+    }
+}