sched/debug: Print each field value left-aligned in sched_show_task()

Currently, the values of some fields are printed right-aligned, causing
the field value to be next to the next field name rather than next to its
own field name. So print each field value left-aligned, to make it more
readable.

 Before:
	stack:    0 pid:  307 ppid:     2 flags:0x00000008
 After:
	stack:0     pid:308   ppid:2      flags:0x0000000a

This also makes them print in the same style as the other two fields:

	task:demo0           state:R  running task

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lore.kernel.org/r/20220727060819.1085-1-thunder.leizhen@huawei.com