hwrng: optee - Use UUID API for exporting the UUID

There is export_uuid() function which exports uuid_t to the u8 array.
Use it instead of open coding variant.

This allows to hide the uuid_t internals.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/char/hw_random/optee-rng.c

@@ -226,7 +226,7 @@ static int optee_rng_probe(struct device *dev)
 		return -ENODEV;
 
 	/* Open session with hwrng Trusted App */
-	memcpy(sess_arg.uuid, rng_device->id.uuid.b, TEE_IOCTL_UUID_LEN);
+	export_uuid(sess_arg.uuid, &rng_device->id.uuid);
 	sess_arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC;
 	sess_arg.num_params = 0;