platform/x86: lenovo-yogabook-wmi: Add support for hall sensor on the back

On the back of the device there is a Hall sensor connected to the
"INT33FF:02" GPIO controller pin 18, which gets triggered when the
device is fully folded into tablet-mode (when the back of the display
touches the back of the keyboard).

Use this to disable both the touch-keyboard and the digitizer when
the tablet is fully folded into tablet-mode.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20211128190031.405620-5-hdegoede@redhat.com