um: time-travel: clean up kernel-doc warnings

Repair all kernel-doc warnings in um_timetravel.h:
- add one enum description
- mark "reserve" as private
- use a leading '@' on current_time

Warning: include/uapi/linux/um_timetravel.h:59 Enum value
 'UM_TIMETRAVEL_SHARED_MAX_FDS' not described in enum
 'um_timetravel_shared_mem_fds'
Warning: include/uapi/linux/um_timetravel.h:245 union member 'reserve'
 not described in 'um_timetravel_schedshm_client'
Warning: include/uapi/linux/um_timetravel.h:288 struct member
 'current_time' not described in 'um_timetravel_schedshm'

Signed-off-by: Randy Dunlap <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Johannes Berg <[email protected]>

Author: rddunlap

include/uapi/linux/um_timetravel.h

@@ -56,6 +56,9 @@ enum um_timetravel_shared_mem_fds {
 	 *	in the control message
 	 */
 	UM_TIMETRAVEL_SHARED_LOGFD,
+	/**
+	 * @UM_TIMETRAVEL_SHARED_MAX_FDS: number of fds listed here
+	 */
 	UM_TIMETRAVEL_SHARED_MAX_FDS,
 };
 
@@ -242,6 +245,7 @@ union um_timetravel_schedshm_client {
 		__u64 req_time;
 		__u64 name;
 	};
+	/* private: */
 	char reserve[128]; /* reserved for future usage */
 };
 
@@ -264,7 +268,7 @@ union um_timetravel_schedshm_client {
  *	is made by any client. Clients also must update this value when they
  *	insert/update an own request into the shared memory while not running
  *	themselves, and the new request is before than the current value.
- * current_time: Current time, can only be set by the client in running state
+ * @current_time: Current time, can only be set by the client in running state
  *	(indicated by @running_id), though that client may only run until @free_until,
  *	so it must remain smaller than @free_until.
  * @running_id: The current client in state running, set before a client is