include/hw/qdev-core: Detect most empty Property lists at compile time

include/hw/qdev-core: Detect most empty Property lists at compile time

Add a macro expansion of device_class_set_props which can check
on the type and size of PROPS before calling the function.

Avoid the macro in migration.c because migration_properties
is defined externally with indeterminate size.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Lei Yang <leiyang@redhat.com>
Link: https://lore.kernel.org/r/20241218134251.4724-13-richard.henderson@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>