drm/msm/dpu: Guard PINGPONG DSC ops behind DPU_PINGPONG_DSC bit

DPU < 7.0.0 has DPU_PINGPONG_DSC feature bit set to indicate it requires
both dpu_hw_pp_setup_dsc() and dpu_hw_pp_dsc_{enable,disable}() to be
executed to complete DSC configuration if DSC hardware block is present.
Hence test DPU_PINGPONG_DSC feature bit and assign DSC related functions
to the ops of PINGPONG block accordingly if DPU_PINGPONG_DSC bit is set.

Changes in v6:
-- split patches, this patch has function handles DPU_PINGPONG_DSC bit

Changes in v9:
-- the original code of assigning dsc related functions to the ops of
   pingpong block without testing the DPU_PINGPONG_DSC feature bit was
   restored back due to rebase error which defeat the purpose of this
   patch. Remove those error code.

Changes in v10:
-- change commit title
-- correct texts at changes in v9

Changes in v12:
-- fixed length too long at Changes in v9
Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Patchwork: https://patchwork.freedesktop.org/patch/539504/
Link: https://lore.kernel.org/r/1685036458-22683-5-git-send-email-quic_khsieh@quicinc.comSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

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

@@ -291,9 +291,12 @@ static void _setup_pingpong_ops(struct dpu_hw_pingpong *c,
 		c->ops.get_line_count = dpu_hw_pp_get_line_count;
 		c->ops.disable_autorefresh = dpu_hw_pp_disable_autorefresh;
 	}
-	c->ops.setup_dsc = dpu_hw_pp_setup_dsc;
-	c->ops.enable_dsc = dpu_hw_pp_dsc_enable;
-	c->ops.disable_dsc = dpu_hw_pp_dsc_disable;
+
+	if (test_bit(DPU_PINGPONG_DSC, &features)) {
+		c->ops.setup_dsc = dpu_hw_pp_setup_dsc;
+		c->ops.enable_dsc = dpu_hw_pp_dsc_enable;
+		c->ops.disable_dsc = dpu_hw_pp_dsc_disable;
+	}
 
 	if (test_bit(DPU_PINGPONG_DITHER, &features))
 		c->ops.setup_dither = dpu_hw_pp_setup_dither;