ARM: dts: qcom: msm8226: Add mdss nodes

Add the nodes that describe the mdss so that display can work on
MSM8226.

Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20230308-msm8226-mdp-v3-7-b6284145d67a@z3ntu.xyz


Signed-off-by: Bjorn Andersson <andersson@kernel.org>