hypervisor: Make vm module private

And thus only export what is necessary through a `pub use`. This is
consistent with some of the other modules and makes it easier to
understand what the external interface of the hypervisor crate is.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

vmm/src/cpu.rs

@@ -34,7 +34,7 @@ use hypervisor::kvm::kvm_bindings;
 use hypervisor::x86_64::{SpecialRegisters, StandardRegisters};
 #[cfg(target_arch = "x86_64")]
 use hypervisor::CpuId;
-use hypervisor::{vm::VmOps, CpuState, HypervisorCpuError, VmExit};
+use hypervisor::{CpuState, HypervisorCpuError, VmExit, VmOps};
 #[cfg(feature = "tdx")]
 use hypervisor::{TdxExitDetails, TdxExitStatus};
 use libc::{c_void, siginfo_t};