soc: microchip: mpfs: simplify error handling in mpfs_blocking_transaction()

The error handling has a kinda weird nested-if setup that is not really
adding anything. Switch it to more of an early return arrangement as a
predatory step for adding different handing for timeouts and failed
services.

Tested-by: Valentina Fernandez <valentina.fernandezalanis@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Author: ConchuOD

drivers/soc/microchip/mpfs-sys-controller.c

@@ -32,28 +32,27 @@ struct mpfs_sys_controller {
 int mpfs_blocking_transaction(struct mpfs_sys_controller *sys_controller, struct mpfs_mss_msg *msg)
 {
 	unsigned long timeout = msecs_to_jiffies(MPFS_SYS_CTRL_TIMEOUT_MS);
-	int ret, err;
+	int ret;
 
-	err = mutex_lock_interruptible(&transaction_lock);
-	if (err)
-		return err;
+	ret = mutex_lock_interruptible(&transaction_lock);
+	if (ret)
+		return ret;
 
 	reinit_completion(&sys_controller->c);
 
 	ret = mbox_send_message(sys_controller->chan, msg);
-	if (ret >= 0) {
-		if (wait_for_completion_timeout(&sys_controller->c, timeout)) {
-			ret = 0;
-		} else {
-			ret = -ETIMEDOUT;
-			dev_warn(sys_controller->client.dev,
-				 "MPFS sys controller transaction timeout\n");
-		}
+	if (ret < 0)
+		goto out;
+
+	if (!wait_for_completion_timeout(&sys_controller->c, timeout)) {
+		ret = -ETIMEDOUT;
+		dev_warn(sys_controller->client.dev, "MPFS sys controller transaction timeout\n");
 	} else {
-		dev_err(sys_controller->client.dev,
-			"mpfs sys controller transaction returned %d\n", ret);
+		/* mbox_send_message() returns positive integers on success */
+		ret = 0;
 	}
 
+out:
 	mutex_unlock(&transaction_lock);
 
 	return ret;