This patch removes the old pmac ide led blink code and
adds generic LED subsystem support for the LED.

It maintains backward compatibility with the old
BLK_DEV_IDE_PMAC_BLINK Kconfig option which now
simply selects the new code and influences the
default trigger.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>