AVIC doorbell is used to notify a running vCPU that interrupts
has been injected into the vCPU AVIC backing page. Current logic
checks only if a VCPU is running before sending a doorbell.
However, the doorbell is not necessary if the destination
CPU is itself.

Add logic to check currently running CPU before sending doorbell.
Signed-off-by: NSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: NAlexander Graf <graf@amazon.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>