Platform: properly fall back to physical DPI scaling.

Not sure why I did it this way. For sure wasn't like that in the initial
implementation.

src/Magnum/Platform/GlfwApplication.cpp

@@ -159,8 +159,7 @@ Vector2 GlfwApplication::dpiScaling(const Configuration& configuration) const {
 
         /* Otherwise ¯\_(ツ)_/¯ */
         #else
-        Debug{verbose} << "Platform::GlfwApplication: sorry, virtual DPI scaling not implemented on this platform yet";
-        return Vector2{1.0f};
+        Debug{verbose} << "Platform::GlfwApplication: sorry, virtual DPI scaling not implemented on this platform yet, falling back to physical DPI scaling";
         #endif
     }
 

src/Magnum/Platform/Sdl2Application.cpp

@@ -180,8 +180,7 @@ Vector2 Sdl2Application::dpiScaling(const Configuration& configuration) const {
 
         /* Otherwise ¯\_(ツ)_/¯ */
         #else
-        Debug{verbose} << "Platform::Sdl2Application: sorry, virtual DPI scaling not implemented on this platform yet";
-        return Vector2{1.0f};
+        Debug{verbose} << "Platform::Sdl2Application: sorry, virtual DPI scaling not implemented on this platform yet, falling back to physical DPI scaling";
         #endif
     }
     #endif