drm/msm/dpu: rename dpu_hw_sspp_cfg to dpu_sw_pipe_cfg

drm/msm/dpu: rename dpu_hw_sspp_cfg to dpu_sw_pipe_cfg

As struct dpu_hw_sspp_cfg describes only the source and destination
rectangles, it is a software pipe configuration now. Rename it
accordingly.

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Tested-by: Abhinav Kumar <quic_abhinavk@quicinc.com> # sc7280
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/527334/
Link: https://lore.kernel.org/r/20230316161653.4106395-14-dmitry.baryshkov@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>