dm kcopyd: remove redundant client counting

Remove client counting code that is no longer needed.

Initialization and destruction is made globally from dm_init and dm_exit and is
not based on client counts. Initialization allocates only one empty slab cache,
so there is no negative impact from performing the initialization always,
regardless of whether some client uses kcopyd or not.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 17f2d6a..9a6023c 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -195,4 +195,7 @@
 int dm_dirty_log_init(void);
 void dm_dirty_log_exit(void);
 
+int dm_kcopyd_init(void);
+void dm_kcopyd_exit(void);
+
 #endif