KVM: x86: Bug the VM, not the kernel, if the ISR count {under,over}flows

Bug the VM, not the host kernel, if KVM's ISR count {under,over}flows when
tracking in-flight ISRs.  There is zero danger to the host if KVM messes up
its IRQ tracking.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Message-ID: <20260618185350.2020845-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>