of: unittest: Fix compile in the non-dynamic case

If CONFIG_OF_KOBJ is not set, a device_node does not contain a
kobj and attempts to access the embedded kobj via kref_read break
the compile.

Replace affected kref_read calls with a macro that reads the
refcount if it exists and returns 1 if there is no embedded kobj.

Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Fixes: 4dde83569832 ("of: Fix double free in of_parse_phandle_with_args_map")
Signed-off-by: Christian A. Ehrhardt <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Herring <[e-mail]>

drivers/of/unittest.c

···
 	failed; \
 })
 
+#ifdef CONFIG_OF_KOBJ
+#define OF_KREF_READ(NODE) kref_read(&(NODE)->kobj.kref)
+#else
+#define OF_KREF_READ(NODE) 1
+#endif
+
 /*
  * Expected message may have a message level other than KERN_INFO.
  * Print the expected message only if the current loglevel will allow
···
 			pr_err("missing testcase data\n");
 			return;
 		}
-		prefs[i] = kref_read(&p[i]->kobj.kref);
+		prefs[i] = OF_KREF_READ(p[i]);
 	}
 
 	rc = of_count_phandle_with_args(np, "phandle-list", "#phandle-cells");
···
 	unittest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);
 
 	for (i = 0; i < ARRAY_SIZE(p); ++i) {
-		unittest(prefs[i] == kref_read(&p[i]->kobj.kref),
+		unittest(prefs[i] == OF_KREF_READ(p[i]),
 			 "provider%d: expected:%d got:%d\n",
-			 i, prefs[i], kref_read(&p[i]->kobj.kref));
+			 i, prefs[i], OF_KREF_READ(p[i]));
 		of_node_put(p[i]);
 	}
 }