drm/msm/mdp5: add writeback block bases

In order to stop patching the mdp5 headers, import definitions for the
writeback blocks. This part is extracted from the old Rob's patch.

Co-developed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/585842/
Link: https://lore.kernel.org/r/20240401-fd-xml-shipped-v5-1-4bdb277a85a1@linaro.org