Improve documentation in generate_test_code.py
diff --git a/tests/Makefile b/tests/Makefile
index e344635..003d71c 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -194,7 +194,7 @@
 		-t suites/main_test.function \
 		-p suites/host_test.function \
 		-s suites  \
-		--help-file suites/helpers.function \
+		--helpers-file suites/helpers.function \
 		-o .
 
 
@@ -229,7 +229,7 @@
 		-t suites/main_test.function \
 		-p suites/target_test.function \
 		-s suites  \
-		--help-file suites/helpers.function \
+		--helpers-file suites/helpers.function \
 		-o ./TESTS/mbedtls/$*
 
 generate-target-tests: $(EMBEDDED_TESTS)