target/*: Add instance_align to all cpu base classes

The omission of alignment has technically been wrong since
269bd5d8f6, where QEMU_ALIGNED was added to CPUTLBDescFast.

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

target/hexagon/cpu.c

@@ -408,6 +408,7 @@ static const TypeInfo hexagon_cpu_type_infos[] = {
         .name = TYPE_HEXAGON_CPU,
         .parent = TYPE_CPU,
         .instance_size = sizeof(HexagonCPU),
+        .instance_align = __alignof(HexagonCPU),
         .instance_init = hexagon_cpu_init,
         .abstract = true,
         .class_size = sizeof(HexagonCPUClass),