rust/vmstate: Remove unnecessary unsafe

Remove the `unsafe` block of vmsd, because vmsd (passed to
vmstate_struct) is defined in Rust side now, and it doesn't need
`unsafe`.

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250318130219.1799170-2-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

rust/qemu-api/src/vmstate.rs

@@ -447,7 +447,7 @@ macro_rules! vmstate_struct {
             },
             size: ::core::mem::size_of::<$type>(),
             flags: $crate::bindings::VMStateFlags::VMS_STRUCT,
-            vmsd: unsafe { $vmsd },
+            vmsd: $vmsd,
             ..$crate::zeroable::Zeroable::ZERO $(
                 .with_varray_flag($crate::call_func_with_field!(
                     $crate::vmstate::vmstate_varray_flag,