refactor: move kvm.rs and mshv.rs into subdirectories

Move kvm.rs → kvm/x86_64.rs and mshv.rs → mshv/x86_64.rs,
adding mod.rs files that re-export through the x86_64 submodule.

This prepares the virtual machine backends for
architecture-specific implementations.

Signed-off-by: Ludvig Liljenberg <4257730+ludfjig@users.noreply.github.com>

Author: ludfjig

src/hyperlight_host/src/hypervisor/virtual_machine/kvm/mod.rs

@@ -0,0 +1,20 @@
+/*
+Copyright 2025  The Hyperlight Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#[cfg(target_arch = "x86_64")]
+mod x86_64;
+#[cfg(target_arch = "x86_64")]
+pub(crate) use x86_64::*;

…st/src/hypervisor/virtual_machine/kvm.rs …hypervisor/virtual_machine/kvm/x86_64.rssrc/hyperlight_host/src/hypervisor/virtual_machine/kvm.rs renamed to src/hyperlight_host/src/hypervisor/virtual_machine/kvm/x86_64.rs src/hyperlight_host/src/hypervisor/virtual_machine/kvm.rs renamed to src/hyperlight_host/src/hypervisor/virtual_machine/kvm/x86_64.rs

@@ -0,0 +1,20 @@
+/*
+Copyright 2025  The Hyperlight Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#[cfg(target_arch = "x86_64")]
+mod x86_64;
+#[cfg(target_arch = "x86_64")]
+pub(crate) use x86_64::*;