drm/msm/dpu: dpu_hw_dspp.h: fix all kernel-doc warnings

drm/msm/dpu: dpu_hw_dspp.h: fix all kernel-doc warnings

Correct or add kernel-doc comments to eliminate all warnings:

Warning: drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.h:33 expecting prototype
 for struct dpu_hw_pcc. Prototype was for struct dpu_hw_pcc_cfg instead
Warning: drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.h:42 Incorrect use of
 kernel-doc format: * setup_pcc - setup dspp pcc
Warning: drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.h:48 struct member
 'setup_pcc' not described in 'dpu_hw_dspp_ops'
Warning: drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.h:76 expecting prototype
 for dpu_hw_dspp(). Prototype was for to_dpu_hw_dspp() instead

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/695652/
Link: https://lore.kernel.org/r/20251219184638.1813181-8-rdunlap@infradead.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>