platform/x86: wmi: Add to_wmi_device() helper macro

Add a helper macro for WMI drivers to cast a device to
the corresponding WMI device. This should replace some
boilerplate code.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20231103182526.3524-2-W_Armin@gmx.de


Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>