build: track MailboxDriver unit tests moved to SecurityCoordinator

Change-Id: I811227abafc3112a6ac1f2e823a5e6737041e312
diff --git a/cantrip_tests.mk b/cantrip_tests.mk
index 92ee54e..bc7bb0b 100644
--- a/cantrip_tests.mk
+++ b/cantrip_tests.mk
@@ -54,7 +54,7 @@
 
 ## Runs cargo unit tests for the MailboxDriver
 cargo_test_mailbox_driver: | cantrip-gen-headers
-	cd $(CANTRIP_COMPONENTS)/MailboxDriver/tests && $(CARGO_TEST)
+	cd $(CANTRIP_COMPONENTS)/SecurityCoordinator/tests && $(CARGO_TEST)
 
 ## Runs cargo unit tests for the opentitan-timer support
 cargo_test_opentitan_timer: | cantrip-gen-headers