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/m68k/cpu.c

@@ -611,6 +611,7 @@ static const TypeInfo m68k_cpus_type_infos[] = {
         .name = TYPE_M68K_CPU,
         .parent = TYPE_CPU,
         .instance_size = sizeof(M68kCPU),
+        .instance_align = __alignof(M68kCPU),
         .instance_init = m68k_cpu_initfn,
         .abstract = true,
         .class_size = sizeof(M68kCPUClass),