KVM: x86: add a tracepoint for APICv/AVIC interrupt delivery

This allows to see how many interrupts were delivered via the
APICv/AVIC from the host.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211209115440.394441-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>