kernel: Split reschdule & pend into irq/spin lock versions

Just like with _Swap(), we need two variants of these utilities which
can atomically release a lock and context switch.  The naming shifts
(for byte count reasons) to _reschedule/_pend_curr, and both have an
_irqlock variant which takes the traditional locking.

Just refactoring.  No logic changes.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
22 files changed