greybus: loopback: convert pr_info to dev_err

This patch fixes and invalid use of pr_info() in favour of dev_err();
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/loopback.c

@@ -450,7 +450,7 @@ static int gb_loopback_transfer(struct gb_loopback *gb, u32 len)
 		goto gb_error;
 
 	if (memcmp(request->data, response->data, len)) {
-		pr_info("%s: Loopback Data doesn't match\n", __func__);
+		dev_err(&gb->connection->dev, "Loopback Data doesn't match\n");
 		retval = -EREMOTEIO;
 	}