leds: class: If no default trigger is given, make hw_control trigger the default...

leds: class: If no default trigger is given, make hw_control trigger the default trigger

If a hw_control_trigger is defined, it's usually desirable to make it
the default trigger. Therefore make it the default trigger, except
the driver explicitly set a default trigger.

Signed-off-by: Heiner Kallweit <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Lee Jones <[email protected]>