drm/msm/dpu: Add writeback support for SM6150

drm/msm/dpu: Add writeback support for SM6150

On the SM6150 platform there is WB_2 block. Add it to the SM6150 catalog.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Fange Zhang <quic_fangez@quicinc.com>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/632337/
Link: https://lore.kernel.org/r/20250114-add-writeback-support-for-sm6150-v2-1-d707b31aad5c@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>