fs/afs/callback.c should #include "cmservice.h"

Every file should include the headers containing the prototypes for
it's global functions.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/fs/afs/callback.c b/fs/afs/callback.c
index 2fd62f8..9cb206e 100644
--- a/fs/afs/callback.c
+++ b/fs/afs/callback.c
@@ -19,6 +19,7 @@
 #include "server.h"
 #include "vnode.h"
 #include "internal.h"
+#include "cmservice.h"
 
 /*****************************************************************************/
 /*