sched/debug: Use symbolic names for task state constants

sched/debug: Use symbolic names for task state constants

include/trace/events/sched.h includes <linux/sched.h> (via
<linux/sched/numa_balancing.h>) and so knows about the TASK_* constants
used to interpret .prev_state. So instead of duplicating the magic
numbers make use of the defined macros to ease understanding the
mapping from state bits to letters which isn't completely intuitive for
an outsider.

Signed-off-by: Uwe Kleine-König <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>