Add missing newline at end of file

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index a8bc45e..62d9d4b 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2243,7 +2243,7 @@
  *
  * Uncomment to enable invasive tests.
  */
-//#define MBEDTLS_TEST_HOOKS
+#define MBEDTLS_TEST_HOOKS
 
 /**
  * \def MBEDTLS_THREADING_ALT