dt-bindings: soc: qcom: add On Chip MEMory (OCMEM) bindings

Add device tree bindings for the On Chip Memory (OCMEM) that is present
on some Qualcomm Snapdragon SoCs.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>