drm/msm/dpu: Implement LM crossbar for v12.0 DPU

v12.0 DPU on SM8750 comes with new LM crossbar that requires each pipe
rectangle to be programmed separately in blend stage.  Implement support
for this along with a new CTL_LAYER_ACTIVE register and setting the
blend stage in layer mixer code.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/659632/
Link: https://lore.kernel.org/r/20250618-b4-sm8750-display-v7-12-a591c609743d@linaro.org


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>