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/mips/cpu.c

@@ -600,6 +600,7 @@ static const TypeInfo mips_cpu_type_info = {
     .name = TYPE_MIPS_CPU,
     .parent = TYPE_CPU,
     .instance_size = sizeof(MIPSCPU),
+    .instance_align = __alignof(MIPSCPU),
     .instance_init = mips_cpu_initfn,
     .abstract = true,
     .class_size = sizeof(MIPSCPUClass),