target-i386/hyperv: Hyper-V SynIC SINT routing and vcpu exit

Hyper-V SynIC(synthetic interrupt controller) helpers for
Hyper-V SynIC irq routing setup, irq injection, irq ack
notifications event/message pages changes tracking for future use.

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Richard Henderson <rth@twiddle.net>
CC: Eduardo Habkost <ehabkost@redhat.com>
CC: "Andreas Färber" <afaerber@suse.de>
CC: Marcelo Tosatti <mtosatti@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
