Input: soc_button_array - silence -ENOENT error on Dell XPS13 9365

The Dell XPS13 9365 has an INT33D2 ACPI node with no GPIOs, causing
the following error in dmesg:

[    7.172275] soc_button_array: probe of INT33D2:00 failed with error -2

This commit silences this, by returning -ENODEV when there are no GPIOs.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=196679


Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>