hypervisor: vmm: Switch to common StandardRegisters implementation

Use the StandardRegisters defined in the hypervisor crate instead of
re-defining it from MSHV/KVM crate.

Signed-off-by: Jinank Jain <jinankjain@microsoft.com>

hypervisor/src/cpu.rs

@@ -9,14 +9,13 @@
 //
 
 #[cfg(target_arch = "aarch64")]
-use crate::aarch64::{RegList, StandardRegisters, VcpuInit};
+use crate::aarch64::{RegList, VcpuInit};
 #[cfg(target_arch = "x86_64")]
 use crate::arch::x86::{CpuIdEntry, FpuState, LapicState, MsrEntry, SpecialRegisters};
 #[cfg(feature = "tdx")]
 use crate::kvm::{TdxExitDetails, TdxExitStatus};
 use crate::CpuState;
 use crate::MpState;
-#[cfg(target_arch = "x86_64")]
 use crate::StandardRegisters;
 use thiserror::Error;
 use vm_memory::GuestAddress;