dm: test: Don't fail when tests are skipped due to build

At present tests that are marked as only for livetree fail when executed
on sandbox_flattree. They cannot actually be executed, but we should not
resport them as 'not found', since this causes errors. Instead, they
should be silently skipped.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/test/dm/test-main.c b/test/dm/test-main.c
index 487d8b9..74f77cc 100644
--- a/test/dm/test-main.c
+++ b/test/dm/test-main.c
@@ -130,7 +130,7 @@
 	const int n_ents = ll_entry_count(struct unit_test, dm_test);
 	struct unit_test_state *uts = &global_dm_test_state;
 	struct unit_test *test;
-	int run_count;
+	int found;
 
 	uts->priv = &_global_priv_dm_test_state;
 	uts->fail_count = 0;
@@ -148,7 +148,7 @@
 	if (!test_name)
 		printf("Running %d driver model tests\n", n_ents);
 
-	run_count = 0;
+	found = 0;
 #ifdef CONFIG_OF_LIVE
 	uts->of_root = gd->of_root;
 #endif
@@ -180,10 +180,10 @@
 			ut_assertok(dm_do_test(uts, test, false));
 			runs++;
 		}
-		run_count += runs;
+		found++;
 	}
 
-	if (test_name && !run_count)
+	if (test_name && !found)
 		printf("Test '%s' not found\n", test_name);
 	else
 		printf("Failures: %d\n", uts->fail_count);