move DMAIN definition to new debug.h

This way both client.h and bankd.h don't conflict with each other

Change-Id: I68ffd64e1f32b90206f98c7f3ea707d7b2e11e61
diff --git a/src/bankd.h b/src/bankd.h
index 86a66b9..86b75cc 100644
--- a/src/bankd.h
+++ b/src/bankd.h
@@ -13,10 +13,7 @@
 #include <osmocom/core/linuxlist.h>
 
 #include "rspro_util.h"
-
-enum {
-	DMAIN,
-};
+#include "debug.h"
 
 struct bankd;