soc: qcom: smd-rpm: Add SM6375 compatible

Add a compatible for the SM6375 SoC.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220921004534.151990-2-konrad.dybcio@somainline.org