platform/x86: wmi: Decouple WMI device removal from wmi_block_list

Use device_for_each_child_reverse() to find and unregister WMI devices
belonging to a WMI bus device instead of iterating thru the entire
wmi_block_list.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20231020211005.38216-6-W_Armin@gmx.de


Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>