drm/msm/dpu: check dpu_plane_atomic_print_state() for valid sspp

Similar to the r_pipe sspp protect, add a check to protect
the pipe state prints to avoid NULL ptr dereference for cases when
the state is dumped without a corresponding atomic_check() where the
pipe->sspp is assigned.

Fixes: 31f7148 ("drm/msm/dpu: move pstate->pipe initialization to dpu_plane_atomic_check")
Reported-by: Stephen Boyd <swboyd@chromium.org>
Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/67
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Stephen Boyd <swboyd@chromium.org> # sc7180-trogdor
Patchwork: https://patchwork.freedesktop.org/patch/628404/
Link: https://lore.kernel.org/r/20241211-check-state-before-dump-v2-1-62647a501e8c@quicinc.com
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>

drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c

@@ -1335,12 +1335,15 @@ static void dpu_plane_atomic_print_state(struct drm_printer *p,
 
 	drm_printf(p, "\tstage=%d\n", pstate->stage);
 
-	drm_printf(p, "\tsspp[0]=%s\n", pipe->sspp->cap->name);
-	drm_printf(p, "\tmultirect_mode[0]=%s\n", dpu_get_multirect_mode(pipe->multirect_mode));
-	drm_printf(p, "\tmultirect_index[0]=%s\n",
-		   dpu_get_multirect_index(pipe->multirect_index));
-	drm_printf(p, "\tsrc[0]=" DRM_RECT_FMT "\n", DRM_RECT_ARG(&pipe_cfg->src_rect));
-	drm_printf(p, "\tdst[0]=" DRM_RECT_FMT "\n", DRM_RECT_ARG(&pipe_cfg->dst_rect));
+	if (pipe->sspp) {
+		drm_printf(p, "\tsspp[0]=%s\n", pipe->sspp->cap->name);
+		drm_printf(p, "\tmultirect_mode[0]=%s\n",
+			   dpu_get_multirect_mode(pipe->multirect_mode));
+		drm_printf(p, "\tmultirect_index[0]=%s\n",
+			   dpu_get_multirect_index(pipe->multirect_index));
+		drm_printf(p, "\tsrc[0]=" DRM_RECT_FMT "\n", DRM_RECT_ARG(&pipe_cfg->src_rect));
+		drm_printf(p, "\tdst[0]=" DRM_RECT_FMT "\n", DRM_RECT_ARG(&pipe_cfg->dst_rect));
+	}
 
 	if (r_pipe->sspp) {
 		drm_printf(p, "\tsspp[1]=%s\n", r_pipe->sspp->cap->name);