dlm: Fix dlm lock status block comment in dlm.h

There is only one place in the dlm where the sb_status is set
and that is queue_cast(). Tracing back the callers of that
function shows that the listed set of return values is
out of date, so here are an updated set.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

include/linux/dlm.h

@@ -48,10 +48,10 @@ typedef void dlm_lockspace_t;
  *
  * 0 if lock request was successful
  * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
- * -ENOMEM if there is no memory to process request
- * -EINVAL if there are invalid parameters
  * -DLM_EUNLOCK if unlock request was successful
  * -DLM_ECANCEL if a cancel completed successfully
+ * -EDEADLK if a deadlock was detected
+ * -ETIMEDOUT if the lock request was canceled due to a timeout
  */
 
 #define DLM_SBF_DEMOTED		0x01