Input: axp20x-pek - only check for "INTCFD9" ACPI device on Cherry Trail

Commit 9b13a4ca ("Input: axp20x-pek - do not register input device
on some systems") added a check for the INTCFD9 ACPI device which also
handles the powerbutton as on some systems the powerbutton is connected
to both the PMIC, handled by axp20x-pek, and to a gpio on the SoC, handled
by soc_button_array which attaches itself to the INTCFD9 ACPI device.

Testing + comparing DSDTs has shown that this only happens on Cherry
Trail devices with an AXP288 PMIC, the AXP288 PMIC is also used on
Bay Trail devices but there the power button is only connected to
the PMIC and not handled by soc_button_array.

This means that the INTCFD9 check has caused a regression on Bay Trail
devices, causing power-button presses to no longer be seen.

This commit fixes this by limiting the check to devices where the ACPI
node for the AXP288 contains a _HRV (hardware revision) attribute with
a value of 3 which indicates we are dealing with a Cherry Trail platform.

Fixes: 9b13a4ca ("Input: axp20x-pek - do not register input ...")
Reported-by: Сергей Трусов <t.rus76@ya.ru>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>