ARM: dts: exynos5422-odroidxu3: Hook up PWM and use it for LEDs

PWM output wasn't working because it wasn't hooked up to its pincontrol.
This patch:
   - hooks up PWM to its pincontrol, and documents what
     the outputs are on the XU3
   - switches the LEDs that are on PWM outputs to use PWM
     rather than GPIO.

The main effect is that the brightness of the LEDs can be controlled, and
user-mode fan control is enabled via /sys/class/pwm

Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>