btrfs: switch btrfs_trans_handle::adding_csums to bool

The semantics of adding_csums matches bool, 'short' was most likely used
to save space in a698d0755adb6f2 ("Btrfs: add a type field for the
transaction handle").

Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index c55e445..a673142 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -118,7 +118,7 @@ struct btrfs_trans_handle {
 	struct btrfs_block_rsv *block_rsv;
 	struct btrfs_block_rsv *orig_rsv;
 	short aborted;
-	short adding_csums;
+	bool adding_csums;
 	bool allocating_chunk;
 	bool can_flush_pending_bgs;
 	bool reloc_reserved;