Free keys after use

Change-Id: I16ba4420ffeb9aa439e0a09a1b34d2aba2e1eb6e
Signed-off-by: Jimmy Brisson <jimmy.brisson@arm.com>
diff --git a/tools/cert_create/src/main.c b/tools/cert_create/src/main.c
index 368493a..31978a9 100644
--- a/tools/cert_create/src/main.c
+++ b/tools/cert_create/src/main.c
@@ -581,6 +581,13 @@
 		}
 	}
 
+	/* If we got here, then we must have filled the key array completely.
+	 * We can then safely call free on all of the keys in the array
+	 */
+	for (i = 0; i < num_keys; i++) {
+		EVP_PKEY_free(keys[i].key);
+	}
+
 #ifndef OPENSSL_NO_ENGINE
 	ENGINE_cleanup();
 #endif