leds: Add IPAQ h1940 LEDs support

This patch adds the support for the IPAQ h1940 leds.

In order to create the amber led (used for the battery charging), the red and
green leds are set to the same default trigger. Due to hardware limitations,
the blue led can only be set in blinking mode.

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>