Default the brightness to 2048 and add possibility to override this in
device tree.
Suggested-by: NRob Clark <robdclark@gmail.com>
Signed-off-by: NBjorn Andersson <bjorn.andersson@sonymobile.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>