platform/x86/intel/vbtn: Stop creating a platform device

platform/x86/intel/vbtn: Stop creating a platform device

Now that "system" devices are represented as platform devices, they
are not claimed by the PNP ACPI scan handler any more and the Intel
virtual button array platform devices should be created by the ACPI
core, so the driver does not need to attempt to create a platform
device by itself.

Accordingly, make it stop doing so.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Link: https://patch.msgid.link/8661724.NyiUUSuA9g@rafael.j.wysocki