arm64: dts: qcom: msm8994: Add OCMEM node

Add OCMEM node to allow for GPU SRAM access.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220319174645.340379-13-konrad.dybcio@somainline.org