drm/msm/dpu: don't use DPU_CLK_CTRL_CURSORn for DMA SSPP clocks

DPU driver has been using the DPU_CLK_CTRL_CURSOR prefix for the DMA
SSPP blocks used for the cursor planes. This has lead to the confusion
at least for the MSM8998 platform. In preparation to supporting the
cursor SSPP blocks, use proper enum values to index DMA SSPP clock
controls.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550 on top of next-20230116
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/522228/
Link: https://lore.kernel.org/r/20230211231259.1308718-14-dmitry.baryshkov@linaro.org
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>