drm/msm/dpu: Clean up CRC debug logs

Currently, dpu_hw_lm_collect_misr returns EINVAL if CRC is disabled.
This causes a lot of spam in the DRM debug logs as it's called for every
vblank.

Instead of returning EINVAL when CRC is disabled in
dpu_hw_lm_collect_misr, let's return ENODATA and add an extra ENODATA check
before the debug log in dpu_crtc_get_crc.

Changes since V1:
- Added reported-by and suggested-by tags
Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Suggested-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Tested-by: Jessica Zhang <quic_jesszhan@quicinc.com> # RB5  (qrb5165)
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/484274/
Link: https://lore.kernel.org/r/20220430005210.339-1-quic_jesszhan@quicinc.comSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

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

@@ -204,7 +204,8 @@ static int dpu_crtc_get_crc(struct drm_crtc *crtc)
 		rc = m->hw_lm->ops.collect_misr(m->hw_lm, &crcs[i]);
 
 		if (rc) {
-			DRM_DEBUG_DRIVER("MISR read failed\n");
+			if (rc != -ENODATA)
+				DRM_DEBUG_DRIVER("MISR read failed\n");
 			return rc;
 		}
 	}

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

@@ -138,7 +138,7 @@ static int dpu_hw_lm_collect_misr(struct dpu_hw_mixer *ctx, u32 *misr_value)
 	ctrl = DPU_REG_READ(c, LM_MISR_CTRL);
 
 	if (!(ctrl & LM_MISR_CTRL_ENABLE))
-		return -EINVAL;
+		return -ENODATA;
 
 	if (!(ctrl & LM_MISR_CTRL_STATUS))
 		return -EINVAL;