mdnie lite control: add 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)

echo 255 150 75 > sys/class/mdnie/mdnie/control_red
(255 = red; 150 = green; 74 = blue)

echo 250 235 255 > sys/class/mdnie/mdnie/control_white
(250 = red; 235 = green; 255 = blue)

override for all samsung modes and profiles is enabled by default:
(echo 1 > /sys/class/mdnie/mdnie/control_override)

small increase on black level (4 = 1,5% of 255] is intended to reduce black crush and smearing effects:
(echo 4 4 4 > /sys/class/mdnie/mdnie/control_black)

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