vmm: Ensure PIO/MMIO exits complete before pausing only for KVM

MSHV does not require to ensure MMIO/PIO exits complete
before pausing. This patch makes sure the above requirement
by checking the hypervisor type run-time.

Fixes #5037

Signed-off-by: Muminul Islam <muislam@microsoft.com>

hypervisor/src/lib.rs

@@ -59,7 +59,7 @@ pub use vm::{
     Vm, VmOps,
 };
 
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub enum HypervisorType {
     #[cfg(feature = "kvm")]
     Kvm,