Replace std::make_tuple with simpler syntax (#77)

* boot2: Simplify g_additional_launch_programs

It appears that Stratosphère is targeting C++17. In C++17,
std::make_tuple is not required for initialisating a tuple anymore.
Same thing, but less typing

* Replace std::make_tuple with {}

More readable and less noise. Also fixes two missing return statements.

stratosphere/pm/source/pm_boot_mode.cpp

@@ -24,10 +24,10 @@ Result BootModeService::handle_deferred() {
 }
 
 std::tuple<Result, bool> BootModeService::get_boot_mode() {
-    return std::make_tuple(0, g_is_maintenance_boot);
+    return {0, g_is_maintenance_boot};
 }
 
 std::tuple<Result> BootModeService::set_maintenance_boot() {
     g_is_maintenance_boot = true;
-    return std::make_tuple(0);
-}
+    return {0};
+}