This consolidates the various board heartbeat LED implementations,
used for strobing the load average across a LED bank. Those boards
not implementing a full bank can hook in via the LED class.
We leave the compat hook in the machvec for now until those non-banked
boards are able to migrate to the drivers/leds.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
3b4d953962