sched/debug: Expose the number of RT/DL tasks that can migrate

Add the value of the rt_rq.rt_nr_migratory and dl_rq.dl_nr_migratory
to the sched_debug output, for instance:

 rt_rq[0]:
   .rt_nr_running                 : 2
   .rt_nr_migratory               : 1     <--- Like this
   .rt_throttled                  : 0
   .rt_time                       : 828.645877
   .rt_runtime                    : 1000.000000

This is useful to debug problems related to the RT/DL schedulers.

This also fixes the format of some variables, that were unsigned, rather
than signed.

Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>
Link: http://lkml.kernel.org/r/7896f71cada54ee7dd8507bb666063a2e051c3d4.1498482127.git.bristot@redhat.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>