platform/x86: dell-privacy: convert to use dev_groups

platform/x86: dell-privacy: convert to use dev_groups

The driver core supports the ability to handle the creation and removal
of device-specific sysfs files in a race-free manner.  Take advantage of
that by converting this driver to use this by moving the sysfs
attributes into a group and assigning the dev_groups pointer to it.

Cc: Perry Yuan <Perry.Yuan@dell.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Mark Gross <markgross@kernel.org>
Cc: Dell.Client.Kernel@dell.com
Cc: platform-driver-x86@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220729115302.2258296-1-gregkh@linuxfoundation.org
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>