event: Add events for device probe/remove

Generate events when devices are probed or removed, allowing hooks
to be added for these situations.

This is controlled by the DM_EVENT config option.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/event.c b/common/event.c
index 366be24..737d3ac 100644
--- a/common/event.c
+++ b/common/event.c
@@ -24,6 +24,12 @@
 const char *const type_name[] = {
 	"none",
 	"test",
+
+	/* Events related to driver model */
+	"dm_pre_probe",
+	"dm_post_probe",
+	"dm_pre_remove",
+	"dm_post_remove",
 };
 
 _Static_assert(ARRAY_SIZE(type_name) == EVT_COUNT, "event type_name size");