platform/x86: intel-vbtn: Use acpi_has_method to check for switch

The check for a device having virtual buttons is done using
acpi_has_method(..."VBDL"). Mimic that for checking virtual switch
presence.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240329143206.2977734-2-gwendal@chromium.org


Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>