log: Add a test command

Add a command which exercises the logging system.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/log/Makefile b/test/log/Makefile
new file mode 100644
index 0000000..b0da8de
--- /dev/null
+++ b/test/log/Makefile
@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2017 Google, Inc
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-$(CONFIG_LOG_TEST) += log_test.o