arm: Fix warning
Add Gamma Control v1.

Thanks to @paranoidandroid for researching what
each gamma value changed so that I could build this interface. It
enables the possibility of tweaking whites, mids, blacks, contrast,
saturation, brightness and greys. This is a full GPL'ed code and easy
to use for any user without any special mumbo jumbo.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Signed-off-by: Derek Cannata <thederekjay@gmail.com>