mm/dmapool.c: change is_page_busy() return from int to bool

This makes the function is_page_busy() return bool rather then an int now
due to this particular function's single return statement only ever
evaulating to either one or zero.
Signed-off-by: NNicholas Krause <xerofoify@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/dmapool.c

@@ -242,7 +242,7 @@ static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
 	return page;
 }
 
-static inline int is_page_busy(struct dma_page *page)
+static inline bool is_page_busy(struct dma_page *page)
 {
 	return page->in_use != 0;
 }