target/avr: Constify VMState in machine.c

Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20231221031652.119827-6-richard.henderson@linaro.org>

target/avr/machine.c

@@ -100,7 +100,7 @@ const VMStateDescription vms_avr_cpu = {
     .name = "cpu",
     .version_id = 1,
     .minimum_version_id = 1,
-    .fields = (VMStateField[]) {
+    .fields = (const VMStateField[]) {
         VMSTATE_UINT32(env.pc_w, AVRCPU),
         VMSTATE_UINT32(env.sp, AVRCPU),
         VMSTATE_UINT32(env.skip, AVRCPU),