drm/msm/adreno: fix gpu probe if no interconnect-names

If there is no interconnect-names, but there is an interconnects
property, then of_icc_get(dev, "gfx-mem"); would return an error
rather than NULL.

Also, if there is no interconnect-names property, there will never
be a ocmem path.  But of_icc_get(dev, "ocmem") would return -EINVAL
instead of -ENODATA.  Just don't bother trying in this case.

v2: explicity check for interconnect-names property

Fixes: 08af4769 ("drm/msm: handle for EPROBE_DEFER for of_icc_get")
Fixes: 00bb9243 ("drm/msm/gpu: add support for ocmem interconnect path")
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/adreno/adreno_gpu.c

@@ -1003,22 +1003,23 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 	if (ret)
 		return ret;
 
-	/* Check for an interconnect path for the bus */
-	gpu->icc_path = of_icc_get(dev, "gfx-mem");
-	if (!gpu->icc_path) {
-		/*
-		 * Keep compatbility with device trees that don't have an
-		 * interconnect-names property.
-		 */
+	/*
+	 * The legacy case, before "interconnect-names", only has a
+	 * single interconnect path which is equivalent to "gfx-mem"
+	 */
+	if (!of_find_property(dev->of_node, "interconnect-names", NULL)) {
 		gpu->icc_path = of_icc_get(dev, NULL);
+	} else {
+		gpu->icc_path = of_icc_get(dev, "gfx-mem");
+		gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
 	}
+
 	if (IS_ERR(gpu->icc_path)) {
 		ret = PTR_ERR(gpu->icc_path);
 		gpu->icc_path = NULL;
 		return ret;
 	}
 
-	gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
 	if (IS_ERR(gpu->ocmem_icc_path)) {
 		ret = PTR_ERR(gpu->ocmem_icc_path);
 		gpu->ocmem_icc_path = NULL;
@@ -1026,6 +1027,7 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 		if (ret != -ENODATA)
 			return ret;
 	}
+
 	return 0;
 }