Gate entropy injection through a dedicated configuration option

Entropy injection has specific testing requirements. Therefore it
should depend on a specific option.
diff --git a/library/version_features.c b/library/version_features.c
index 92b1af1..00fd2e9 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -432,6 +432,9 @@
 #if defined(MBEDTLS_PSA_CRYPTO_SPM)
     "MBEDTLS_PSA_CRYPTO_SPM",
 #endif /* MBEDTLS_PSA_CRYPTO_SPM */
+#if defined(MBEDTLS_PSA_INJECT_ENTROPY)
+    "MBEDTLS_PSA_INJECT_ENTROPY",
+#endif /* MBEDTLS_PSA_INJECT_ENTROPY */
 #if defined(MBEDTLS_RSA_NO_CRT)
     "MBEDTLS_RSA_NO_CRT",
 #endif /* MBEDTLS_RSA_NO_CRT */