Test: Remove unused code from helpers file

Change-Id: I86dd5a803a0d4aa93416864a73bfef05a5c6ffdb
Signed-off-by: Raef Coles <raef.coles@arm.com>
diff --git a/test/framework/test_framework_helpers.c b/test/framework/test_framework_helpers.c
index 46f7171..a467a04 100644
--- a/test/framework/test_framework_helpers.c
+++ b/test/framework/test_framework_helpers.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2017-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
@@ -9,31 +9,6 @@
 
 #include <stdio.h>
 
-const char *asset_perms_to_str(uint8_t permissions)
-{
-    switch (permissions) {
-    case 0:
-        return "No permissions";
-    case 1:
-        return "SECURE_ASSET_REFERENCE";
-    case 2:
-        return "SECURE_ASSET_WRITE";
-    case 3:
-        return "SECURE_ASSET_REFERENCE | SECURE_ASSET_WRITE";
-    case 4:
-        return "SECURE_ASSET_READ";
-    case 5:
-        return "SECURE_ASSET_REFERENCE | SECURE_ASSET_READ";
-    case 6:
-        return "SECURE_ASSET_WRITE | SECURE_ASSET_READ";
-    case 7:
-        return "SECURE_ASSET_REFERENCE | SECURE_ASSET_WRITE | "
-               "SECURE_ASSET_READ";
-    default:
-        return "Unknown permissions";
-    }
-}
-
 void printf_set_color(enum serial_color_t color_id)
 {
     TEST_LOG("\33[%dm", color_id);