platform/x86: wmi: linux/wmi.h: fix Excess kernel-doc description warning

platform/x86: wmi: linux/wmi.h: fix Excess kernel-doc description warning

Remove the "private:" comment to prevent the kernel-doc warning:

include/linux/wmi.h:27: warning: Excess struct member 'setable' description in 'wmi_device'

Either a struct member is documented (via kernel-doc) or it's private,
but not both.

Fixes: b4cc979588ee ("platform/x86: wmi: Add kernel doc comments")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Armin Wolf <W_Armin@gmx.de>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Cc: platform-driver-x86@vger.kernel.org
Reviewed-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20231223194321.23084-1-rdunlap@infradead.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>