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/drivers/core/device-remove.c b/drivers/core/device-remove.c
index e6ec6ff..73d2e9e 100644
--- a/drivers/core/device-remove.c
+++ b/drivers/core/device-remove.c
@@ -207,6 +207,10 @@
 	if (!(dev_get_flags(dev) & DM_FLAG_ACTIVATED))
 		return 0;
 
+	ret = device_notify(dev, EVT_DM_PRE_REMOVE);
+	if (ret)
+		return ret;
+
 	/*
 	 * If the child returns EKEYREJECTED, continue. It just means that it
 	 * didn't match the flags.
@@ -256,6 +260,10 @@
 
 	dev_bic_flags(dev, DM_FLAG_ACTIVATED);
 
+	ret = device_notify(dev, EVT_DM_POST_REMOVE);
+	if (ret)
+		goto err_remove;
+
 	return 0;
 
 err_remove: