CMake: bug-fix for tvOS support

tvOS Device support wasn't working, at least not with the current-latest tvOS release (13.0), with CMake failing during its configuration stage.

CMakeLists.txt

@@ -1532,10 +1532,10 @@ elseif(APPLE)
     else()
       file(GLOB POWER_SOURCES ${SDL2_SOURCE_DIR}/src/power/macosx/*.c)
       set(SDL_POWER_MACOSX 1)
+      set(SDL_FRAMEWORK_IOKIT 1)
     endif()
     set(SOURCE_FILES ${SOURCE_FILES} ${POWER_SOURCES})
     set(HAVE_SDL_POWER TRUE)
-    set(SDL_FRAMEWORK_IOKIT 1)
   endif()
 
   if(SDL_TIMERS)