drm/i915/display: Add meaningful traces for QGV point info error handling

For debug purposes we need those - error path won't flood the log,
however there has been already numerous cases, when due to lack
of debugs, we couldn't immediately tell what was the problem on
customer machine, which slowed down the investigation, requiring
to get access to target device and adding those traces manually.

v2: - Make the debug more generic and move it to intel_dram_detect
      (Gustavo Sousa)
v3: - Use %u for unsigned variable in debug prints (Gustavo)
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240405113533.338553-2-vinod.govindapillai@intel.com

drivers/gpu/drm/i915/display/intel_bw.c

@@ -290,8 +290,10 @@ static int icl_get_qgv_points(struct drm_i915_private *dev_priv,
 		struct intel_qgv_point *sp = &qi->points[i];
 
 		ret = intel_read_qgv_point_info(dev_priv, sp, i);
-		if (ret)
+		if (ret) {
+			drm_dbg_kms(&dev_priv->drm, "Could not read QGV %d info\n", i);
 			return ret;
+		}
 
 		drm_dbg_kms(&dev_priv->drm,
 			    "QGV %d: DCLK=%d tRP=%d tRDPRE=%d tRAS=%d tRCD=%d tRC=%d\n",

drivers/gpu/drm/i915/soc/intel_dram.c

@@ -681,6 +681,8 @@ void intel_dram_detect(struct drm_i915_private *i915)
 	if (ret)
 		return;
 
+	drm_dbg_kms(&i915->drm, "Num qgv points %u\n", dram_info->num_qgv_points);
+
 	drm_dbg_kms(&i915->drm, "DRAM channels: %u\n", dram_info->num_channels);
 
 	drm_dbg_kms(&i915->drm, "Watermark level 0 adjustment needed: %s\n",