timerqueue: Split out timerqueue_types.h

Trimming down sched.h dependencies: timerqueue_types can include just
rbtree_types.h instead of pulling in rbtree.h.

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

hrtimers: Split out hrtimer_types.h

We need to reduce the scope of what's included in sched.h: task_struct
includes a hrtimer, so split out the core types into their own header.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Thomas Gleixner <tglx@linutronix.de>