kernel: Add _unlocked() variant to context switch primitives

These functions, for good design reason, take a locking key to
atomically release along with the context swtich.  But there's still a
common pattern in code to do a switch unconditionally by passing
irq_lock() directly.  On SMP that's a little hurtful as it spams the
global lock.  Provide an _unlocked() variant for
_Swap/_reschedule/_pend_curr for simplicity and efficiency.

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