Add the compatible for the MDSS client on the Snapdragon 670 so it can
be properly configured by the IOMMU driver.

Otherwise, there is an unhandled context fault.
Signed-off-by: Richard Acayan <mailingradian@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20230925234246.900351-3-mailingradian@gmail.comSigned-off-by: Will Deacon <will@kernel.org>