platform/x86: panasonic-laptop: Convert ACPI driver to a platform one

platform/x86: panasonic-laptop: Convert ACPI driver to a platform one

In all cases in which a struct acpi_driver is used for binding a driver
to an ACPI device object, a corresponding platform device is created by
the ACPI core and that device is regarded as a proper representation of
underlying hardware.  Accordingly, a struct platform_driver should be
used by driver code to bind to that device.  There are multiple reasons
why drivers should not bind directly to ACPI device objects [1].

Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the Panasonic laptop ACPI driver to a platform
one.

While this is not expected to alter functionality, it changes sysfs
layout and so it will be visible to user space.

To maintain backwards compatibility with possibly existing user space,
the sysfs attributes created by the driver under the ACPI device object
used by it are not relocated.  Accordingly, the driver will continue to
use the driver_data pointer in struct acpi_device which needs to be
cleared on driver removal.

Link: https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/8664183.T7Z3S40VBb@rafael.j.wysocki
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>