msm: mdss: Display gamma control

TODO: confirm rgb channels, identify other tunables, cleanup,
apply values without switching screen (off and) on.

sysfs: /sys/devices/qcom,mdss_dsi_jdi_command_ors.69/*

Conflicts:
	drivers/video/msm/mdss/mdss_dsi_panel.c
Merge branch 'kk4.4' of https://github.com/kejar31/android_kernel_oneplus_msm8974 into kk4.4