Move MBEDTLS_CTR_DRBG_USE_128_BIT_KEY to the correct section

It's an on/off feature, so it should be listed in version_features.
diff --git a/library/version_features.c b/library/version_features.c
index 6882830..d60758c 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -306,6 +306,9 @@
 #if defined(MBEDTLS_CIPHER_PADDING_ZEROS)
     "MBEDTLS_CIPHER_PADDING_ZEROS",
 #endif /* MBEDTLS_CIPHER_PADDING_ZEROS */
+#if defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
+    "MBEDTLS_CTR_DRBG_USE_128_BIT_KEY",
+#endif /* MBEDTLS_CTR_DRBG_USE_128_BIT_KEY */
 #if defined(MBEDTLS_ENABLE_WEAK_CIPHERSUITES)
     "MBEDTLS_ENABLE_WEAK_CIPHERSUITES",
 #endif /* MBEDTLS_ENABLE_WEAK_CIPHERSUITES */