KVM: x86: Add information about pending requests to kvm_exit tracepoint

Print pending requests in the kvm_exit tracepoint, which allows userspace
to gather information on how often KVM interrupts vCPUs due to specific
requests.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20240910200350.264245-3-mlevitsk@redhat.com


[sean: massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>