dt-bindings: arm: qcom: Document MSM8226 SoC binding

Document the MSM8226 SoC device-tree binding.

Signed-off-by: Bartosz Dudziak <bartosz.dudziak@snejp.pl>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210418122909.71434-5-bartosz.dudziak@snejp.pl


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