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/*
msm: mdss: Apply commands values without switching screen (off and) on
msm: mdss: Remove tunable for command 32

Even slight changes look ugly or distort the screen.
msm: mdss: distinguish between Gamma RGB polarity Positive/Negative

Signed-off-by: Paul Reioux <reioux@gmail.com>