MCUXpresso: Update LPC TRNG driver

Signed-off-by: Mahesh Mahadevan <mahesh.mahadevan@nxp.com>

targets/TARGET_NXP/TARGET_MCUXpresso_MCUS/TARGET_LPC55S69/trng_api.c

@@ -0,0 +1,47 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2018 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "trng_api.h"
+
+#if defined(DEVICE_TRNG)
+#include "fsl_rng.h"
+
+void trng_init(trng_t *obj)
+{
+    /* Init RNGA */
+    RNG_Init(RNG);
+}
+
+void trng_free(trng_t *obj)
+{
+    RNG_Deinit(RNG);
+}
+
+int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
+{
+    status_t status;
+
+    /* Get Random data*/
+    status = RNG_GetRandomData(RNG, output, length);
+    if (status == kStatus_Success) {
+        *output_length = length;
+        return 0;
+    } else {
+        return -1;
+    }
+}
+
+#endif