FIH: Refine the usage of FIH tool

1. Make it skip the build if tfm_s.axf exists. Users can alse
   re-build the source code if necessary.
2. Add the support of certain function test

Signed-off-by: Jianliang Shen <jianliang.shen@arm.com>
Change-Id: Id99cf6d9f65da3ea7fe8c3b167cd06ac53d053b9
diff --git a/fih_test_tool/fih_test b/fih_test_tool/fih_test
index dafdf53..953f4af 100755
--- a/fih_test_tool/fih_test
+++ b/fih_test_tool/fih_test
@@ -1,11 +1,11 @@
 #!/usr/bin/env bash
-# Copyright (c) 2021, Arm Limited. All rights reserved.
+# Copyright (c) 2021-2022, Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
 usage()
 {
-    echo "$0 [-s source_dir] [-d build_dir] [-b <build_type>] [-c <compiler>] [-f <fih_profile>] [-l <tfm_level>]"
+    echo "$0 [-s source_dir] [-d build_dir] [-b <build_type>] [-c <compiler>] [-p <fih_profile>] [-l <tfm_level>] [-f <function>] [-r]"
 }
 
 # Parse arguments
@@ -31,7 +31,7 @@
         shift
         shift
         ;;
-        -f|--fih_profile)
+        -p|--fih_profile)
         FIH_PROFILE="$2"
         shift
         shift
@@ -41,6 +41,16 @@
         shift
         shift
         ;;
+        -f|--function)
+        FUNCTION="$2"
+        shift
+        shift
+        ;;
+        -r|--re-build)
+        RE_BUILD=1
+        shift
+        shift
+        ;;
         -h|--help)
         usage
         exit 0