fix missing include

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/tests/suites/test_suite_md.function b/tests/suites/test_suite_md.function
index 2768707..75087e7 100644
--- a/tests/suites/test_suite_md.function
+++ b/tests/suites/test_suite_md.function
@@ -1,5 +1,6 @@
 /* BEGIN_HEADER */
 #include "mbedtls/md.h"
+#include "../library/md_psa.h"
 /* END_HEADER */
 
 /* BEGIN_DEPENDENCIES