Added header for SDL_Delay()

src/joystick/iphoneos/SDL_mfijoystick.m

@@ -25,6 +25,7 @@
 #include "SDL_joystick.h"
 #include "SDL_hints.h"
 #include "SDL_stdinc.h"
+#include "SDL_timer.h"
 #include "../SDL_sysjoystick.h"
 #include "../SDL_joystick_c.h"
 #include "../hidapi/SDL_hidapijoystick_c.h"