btrfs: make 1-bit bit-fields of scrub_page unsigned int

The bitfields have_csum and io_error are currently signed which is not
recommended as the representation is an implementation defined
behaviour. Fix this by making the bit-fields unsigned ints.

Fixes: 2c363954 ("btrfs: scrub: remove the anonymous structure from scrub_page")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/scrub.c

@@ -73,8 +73,8 @@ struct scrub_page {
 	u64			physical_for_dev_replace;
 	atomic_t		refs;
 	u8			mirror_num;
-	int			have_csum:1;
-	int			io_error:1;
+	unsigned int		have_csum:1;
+	unsigned int		io_error:1;
 	u8			csum[BTRFS_CSUM_SIZE];
 
 	struct scrub_recover	*recover;