test: ofnode: test ofnode_device_is_compatible()

Test ofnode_device_is_compatible(), and also ofnode_path().

Requested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/Makefile b/test/dm/Makefile
index f500bf1..5511a85 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -21,6 +21,7 @@
 obj-$(CONFIG_LED) += led.o
 obj-$(CONFIG_DM_MAILBOX) += mailbox.o
 obj-$(CONFIG_DM_MMC) += mmc.o
+obj-y += ofnode.o
 obj-$(CONFIG_DM_PCI) += pci.o
 obj-$(CONFIG_PHY) += phy.o
 obj-$(CONFIG_POWER_DOMAIN) += power-domain.o