Fix Windows Tablet API preference not being used

It was sometimes set before reading preferences, now it's passed to GHOST every
time preferences are read.

Differential Revision: https://developer.blender.org/D5641

source/blender/windowmanager/intern/wm_files.c

@@ -375,6 +375,9 @@ static void wm_init_userdef(Main *bmain)
 
   /* update tempdir from user preferences */
   BKE_tempdir_init(U.tempdir);
+
+  /* Update tablet API preference. */
+  WM_init_tablet_api();
 }
 
 /* return codes */

source/blender/windowmanager/intern/wm_window.c

@@ -1679,8 +1679,6 @@ void wm_ghost_init(bContext *C)
     }
 
     GHOST_UseWindowFocus(wm_init_state.window_focus);
-
-    WM_init_tablet_api();
   }
 }