ARM: dts: qcom: msm8974-hammerhead: add support for display

Add initial support for the display found on the LG Nexus 5 (hammerhead)
phone. This is based on work from Jonathan Marek.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>