dlm: common max length definitions

Add central definitions for max lockspace name length and max resource
name length.  The lack of central definitions has resulted in scattered
private definitions which we can now clean up, including an unused one
in dlm_device.h.

Signed-off-by: David Teigland <teigland@redhat.com>

include/linux/dlmconstants.h

@@ -18,6 +18,10 @@
  * Constants used by DLM interface.
  */
 
+#define DLM_LOCKSPACE_LEN       64
+#define DLM_RESNAME_MAXLEN      64
+
+
 /*
  * Lock Modes
  */