btrfs: declare TRACE_DEFINE_ENUM for each of show_flush_state enum

So that perf can show the state symbol.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

include/trace/events/btrfs.h

@@ -28,6 +28,13 @@ struct btrfs_qgroup_extent_record;
 struct btrfs_qgroup;
 struct prelim_ref;
 
+TRACE_DEFINE_ENUM(FLUSH_DELAYED_ITEMS_NR);
+TRACE_DEFINE_ENUM(FLUSH_DELAYED_ITEMS);
+TRACE_DEFINE_ENUM(FLUSH_DELALLOC);
+TRACE_DEFINE_ENUM(FLUSH_DELALLOC_WAIT);
+TRACE_DEFINE_ENUM(ALLOC_CHUNK);
+TRACE_DEFINE_ENUM(COMMIT_TRANS);
+
 #define show_ref_type(type)						\
 	__print_symbolic(type,						\
 		{ BTRFS_TREE_BLOCK_REF_KEY, 	"TREE_BLOCK_REF" },	\