mm/pagemap: Clenaup PREEMPT_COUNT leftovers

CONFIG_PREEMPT_COUNT is now unconditionally enabled and will be
removed. Cleanup the leftovers before doing so.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org

include/linux/pagemap.h

@@ -168,9 +168,7 @@ void release_pages(struct page **pages, int nr);
 static inline int __page_cache_add_speculative(struct page *page, int count)
 {
 #ifdef CONFIG_TINY_RCU
-# ifdef CONFIG_PREEMPT_COUNT
-	VM_BUG_ON(!in_atomic() && !irqs_disabled());
-# endif
+	VM_BUG_ON(preemptible())
 	/*
 	 * Preempt must be disabled here - we rely on rcu_read_lock doing
 	 * this for us.