dma-pool: Fix an uninitialized variable bug in atomic_pool_expand()

commit 892fc9f upstream.

The "page" pointer can be used with out being initialized.

Fixes: d7e673e ("dma-pool: Only allocate from CMA when in same memory zone")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/dma/pool.c

@@ -84,7 +84,7 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
 			      gfp_t gfp)
 {
 	unsigned int order;
-	struct page *page;
+	struct page *page = NULL;
 	void *addr;
 	int ret = -ENOMEM;