hypervisor, arch: Fix warnings introduced in hypervisor crate

This commit fixes some warnings introduced in the previous
hyperviosr crate PR.Removed some unused variables from arch/aarch64
module.

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

hypervisor/src/hypervisor.rs

@@ -10,7 +10,7 @@
 use crate::vm::Vm;
 #[cfg(target_arch = "x86_64")]
 use crate::x86_64::CpuId;
-
+#[cfg(target_arch = "x86_64")]
 use kvm_ioctls::Cap;
 use std::sync::Arc;
 

hypervisor/src/kvm/mod.rs

@@ -11,6 +11,7 @@
 use kvm_ioctls::{NoDatamatch, VcpuFd, VmFd};
 use std::result;
 use std::sync::Arc;
+#[cfg(target_arch = "x86_64")]
 use vm_memory::Address;
 use vmm_sys_util::eventfd::EventFd;
 
@@ -617,6 +618,7 @@ impl cpu::Vcpu for KvmVcpu {
 
         Ok(())
     }
+    #[allow(unused_variables)]
     #[cfg(target_arch = "aarch64")]
     fn set_cpu_state(&self, state: &CpuState) -> cpu::Result<()> {
         Ok(())