dlm: eliminate astparam type casting

Put lkb_astparam in a union with a dlm_user_args pointer to
eliminate a lot of type casting.

Signed-off-by: David Teigland <teigland@redhat.com>
diff --git a/fs/dlm/debug_fs.c b/fs/dlm/debug_fs.c
index 12c3bfd..52b1196 100644
--- a/fs/dlm/debug_fs.c
+++ b/fs/dlm/debug_fs.c
@@ -162,14 +162,12 @@
 
 static void print_lock(struct seq_file *s, struct dlm_lkb *lkb, struct dlm_rsb *r)
 {
-	struct dlm_user_args *ua;
 	unsigned int waiting = 0;
 	uint64_t xid = 0;
 
 	if (lkb->lkb_flags & DLM_IFL_USER) {
-		ua = (struct dlm_user_args *) lkb->lkb_astparam;
-		if (ua)
-			xid = ua->xid;
+		if (lkb->lkb_ua)
+			xid = lkb->lkb_ua->xid;
 	}
 
 	if (lkb->lkb_timestamp)