This patch adds New driver to support:
1. Supports ADC IF found on EXYNOS4412/EXYNOS5250
   and future SoCs from Samsung
2. Add ADC driver under iio/adc framework
3. Also adds the Documentation for device tree bindings
Signed-off-by: NNaveen Krishna Chatradhi <ch.naveen@samsung.com>
Reviewed-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>