Remove more bad uses of dp_xres. Fix a data flow issue

(could end up with "feedback" if modifying the screen bounds)

Core/Config.cpp

@@ -696,6 +696,7 @@ void Config::Load(const char *iniFileName, const char *controllerIniFilename) {
 	}
 
 	// MIGRATION: For users who had the old static touch layout, aren't I nice?
+	// We can probably kill this in 0.9.8 or something.
 	if (fDpadX > 1.0 || fDpadY > 1.0) { // Likely the rest are too!
 		float screen_width = dp_xres;
 		float screen_height = dp_yres;