[ARM] omap: resource: Make free_user() static

Only resource framework calls free_user(), ensure it is this way.

Change-Id: Iea543a009126216b6d3b607595d0b799bf0ef2e9
Signed-off-by: Mike Chan <mike@android.com>

arch/arm/plat-omap/resource.c

@@ -190,7 +190,7 @@ static struct users_list *get_user(void)
  * dynamically allocated, and if its from the static pool, marks it unused.
  * No return value.
  */
-void free_user(struct users_list *user)
+static void free_user(struct users_list *user)
 {
 	if (user->usage == DYNAMIC_ALLOC) {
 		kfree(user);