Convert VMI timer to use clock events, making it properly able to use the NO_HZ
infrastructure.  On UP systems, with no local APIC, we just continue to route
these events through the PIT.  On systems with a local APIC, or SMP, we provide
a single source interrupt chip which creates the local timer IRQ.  It actually
gets delivered by the APIC hardware, but we don't want to use the same local
APIC clocksource processing, so we create our own handler here.
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andi Kleen <ak@suse.de>
CC: Dan Hecht <dhecht@vmware.com>
CC: Ingo Molnar <mingo@elte.hu>
CC: Thomas Gleixner <tglx@linutronix.de>