ARM: EXYNOS4: Add PWM backlight support on ORIGEN

This patch adds support for LCD backlight using PWM timer
on ORIGEN board.

Signed-off-by: Giridhar Maruthy <giridhar.maruthy@linaro.org>
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>