Simple switchable mdnie lite control interface

- make hijacking STANDARD mode sysfs switchable
- add copy curve information from existing mode

Activate the MDNIE control (hijack STANDARD mode):
echo 1 > /sys/class/mdnie/mdnie/hijack

Copy system gain curves to user configurable profile:
echo x > /sys/class/mdnie/mdnie/curve

where X equals :
- 0 = curve 0.20 [Natural/Movie]
- 1 = curve 0.08 [Standard/Auto]
- 3 = curve 0.06 [Dynamic]

modified by WhatHub