btrfs: fix bool type in btrfs_page_exists_in_range

We use only a simple bool indicator, int is not a problem here.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -7486,7 +7486,7 @@ noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
 {
 	struct radix_tree_root *root = &inode->i_mapping->page_tree;
-	int found = false;
+	bool found = false;
 	void **pagep = NULL;
 	struct page *page = NULL;
 	unsigned long start_idx;