posix-timers: Show clock ID in proc file

Expand information about posix-timers in /proc/<pid>/timers by adding
info about clock, with which the timer was created. I.e. in the forth
line of timer info after "notify:" line go "ClockID: <clock_id>".

Signed-off-by: Pavel Tikhomirov <[email protected]>
Cc: Michael Kerrisk <[email protected]>
Cc: Matthew Helsley <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>

fs/proc/base.c

@@ -2118,6 +2118,7 @@ static int show_timer(struct seq_file *m, void *v)
 		nstr[notify & ~SIGEV_THREAD_ID],
 		(notify & SIGEV_THREAD_ID) ? "tid" : "pid",
 		pid_nr_ns(timer->it_pid, tp->ns));
+	seq_printf(m, "ClockID: %d\n", timer->it_clock);
 
 	return 0;
 }