mdnie lite control: add initial control interface
compatible with mdnie lite engine used by samsung qualcomm variants I9505/N9005.

sysfs controls for RGBYCMWK channel and "sharpen" effect:
(sys/class/mdnie/mdnie)

there is also a override that replaces "Standard mode"
accesseable under [Settings]->[Display]->[Screen mode] or:
(echo 1 > /sys/class/mdnie/mdnie/mode)

small increase on black level (=5) [or 1,5%+] is intended so reduce black crush and smearing effects.

idea based on (mDNIe colour and brightness control) by AndreiLux.