emulator: Fix status value for DHKey Complete event

The value wasn't properly initialized, leading to arbitrary values.
diff --git a/emulator/btdev.c b/emulator/btdev.c
index 38769d8..1e94fc3 100644
--- a/emulator/btdev.c
+++ b/emulator/btdev.c
@@ -3098,6 +3098,7 @@
 		}
 		cmd_status(btdev, BT_HCI_ERR_SUCCESS,
 						BT_HCI_CMD_LE_GENERATE_DHKEY);
+		dh_evt.status = BT_HCI_ERR_SUCCESS;
 		le_meta_event(btdev, BT_HCI_EVT_LE_GENERATE_DHKEY_COMPLETE,
 						&dh_evt, sizeof(dh_evt));
 		break;