Enable support for device ID structures that do not contain
context/data field (usually named `driver_data`), making the trait
usable in a wider range of subsystems and buses.
Several such structures are defined in
include/linux/mod_devicetable.h.
This refactoring is a preparation for enabling the PHY abstractions to
use device_id trait.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxx>