btrfs: don't use UAPI types for fiemap callback

The fiemap callback is not part of UAPI interface and the prototypes
don't have the __u64 types either.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -4669,7 +4669,7 @@ static int emit_last_fiemap_cache(struct fiemap_extent_info *fieinfo,
 }
 
 int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
-		__u64 start, __u64 len)
+		  u64 start, u64 len)
 {
 	int ret = 0;
 	u64 off = start;

fs/btrfs/extent_io.h

@@ -204,7 +204,7 @@ int btree_write_cache_pages(struct address_space *mapping,
 			    struct writeback_control *wbc);
 void extent_readahead(struct readahead_control *rac);
 int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
-		__u64 start, __u64 len);
+		  u64 start, u64 len);
 void set_page_extent_mapped(struct page *page);
 
 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,

fs/btrfs/inode.c

@@ -7946,7 +7946,7 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 }
 
 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
-		__u64 start, __u64 len)
+			u64 start, u64 len)
 {
 	int	ret;