device: Add device path display support

Add an optional routine to translate the device path types into a string
for display.

TEST=Build and run on Galileo

Change-Id: Iea5d0a2430d9a8546105324e2beda0955210dca9
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-on: https://review.coreboot.org/13715
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/device/device_util.c

@@ -921,3 +921,15 @@ int dev_count_cpu(void)
 
 	return count;
 }
+
+/* Get device path name */
+const char *dev_path_name(enum device_path_type type)
+{
+	static const char *const type_names[] = DEVICE_PATH_NAMES;
+	const char *type_name = "Unknown";
+
+	/* Translate the type value into a string */
+	if (type < ARRAY_SIZE(type_names))
+		type_name = type_names[type];
+	return type_name;
+}