Build: Support TF-M split build feature

TF-M build commands are changed by new feature "split build".
Update CI scripts to support this feature.

Signed-off-by: Xinyu Zhang <xinyu.zhang@arm.com>
Change-Id: If5a81ca7a1bd99ac8fb9f4850be89b48b76fcbe2
diff --git a/configs.py b/configs.py
index faef7f2..e83c7d9 100755
--- a/configs.py
+++ b/configs.py
@@ -73,7 +73,7 @@
         "-b",
         "--build_commands",
         default=None,
-        choices=['set_compiler', 'cmake_config', 'cmake_build', 'post_build'],
+        choices=['set_compiler', 'spe_cmake_config', 'nspe_cmake_config', 'spe_cmake_build', 'nspe_cmake_build', 'post_build'],
         help="Print selected type of build commands to be run for current configuration."
     )
     PARSER.add_argument(