sched: Do not shadow task_info in struct task.

sched: Do not shadow task_info in struct task.

All fields of struct task_info have direct counterparts in struct
task. The fields of struct task are initialized in task_register()
to the corresponding fields of struct task_info. It's easier to
just embed a task_info structure in struct task instead. This also
guarantees that task_register() stays correct in case another field
is added to struct task_info.