Enable test generation from bignum_mod.py

Signed-off-by: Werner Lewis <werner.lewis@arm.com>
diff --git a/tests/Makefile b/tests/Makefile
index 0b31cdd..2d2d70a 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -95,6 +95,7 @@
 generated_bignum_test_data: ../scripts/mbedtls_dev/bignum_common.py
 generated_bignum_test_data: ../scripts/mbedtls_dev/bignum_core.py
 generated_bignum_test_data: ../scripts/mbedtls_dev/bignum_mod_raw.py
+generated_bignum_test_data: ../scripts/mbedtls_dev/bignum_mod.py
 generated_bignum_test_data: ../scripts/mbedtls_dev/test_case.py
 generated_bignum_test_data: ../scripts/mbedtls_dev/test_data_generation.py
 generated_bignum_test_data: