arch, vmm: Pass cpu topology configuation to FDT

In an Arm system, the hierarchy of CPUs is defined through three
entities that are used to describe the layout of physical CPUs in
the system:

- cluster
- core
- thread

All these three entities have their own FDT node field. Therefore,
This commit adds an AArch64-specific helper to pass the config from
the Cloud Hypervisor command line to the `configure_system`, where
eventually the `create_fdt` is called.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>

arch/src/aarch64/mod.rs

@@ -135,10 +135,12 @@ pub fn arch_memory_regions(size: GuestUsize) -> Vec<(GuestAddress, usize, Region
 }
 
 /// Configures the system and should be called once per vm before starting vcpu threads.
+#[allow(clippy::too_many_arguments)]
 pub fn configure_system<T: DeviceInfoForFdt + Clone + Debug, S: ::std::hash::BuildHasher>(
     guest_mem: &GuestMemoryMmap,
     cmdline_cstring: &CStr,
     vcpu_mpidr: Vec<u64>,
+    vcpu_topology: Option<(u8, u8, u8)>,
     device_info: &HashMap<(DeviceType, String), T, S>,
     initrd: &Option<super::InitramfsConfig>,
     pci_space_address: &(u64, u64),
@@ -148,6 +150,7 @@ pub fn configure_system<T: DeviceInfoForFdt + Clone + Debug, S: ::std::hash::Bui
         guest_mem,
         cmdline_cstring,
         vcpu_mpidr,
+        vcpu_topology,
         device_info,
         gic_device,
         initrd,