Add a "struct device *dev" local variable to probe().

This is a preparation patch for making lenovo-yogabook-wmi also work
on the Android version of the Yoga Book 1 which does not have a WMI
interface to deal with toggling the keyboard half between
touch-keyboard and wacom-digitizer mode.

While at it also move the dev_set_drvdata() call to the end of probe().
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230430165807.472798-9-hdegoede@redhat.com