net: context: Remove shadowing variable in net_context_recv()

Remove the shadowing ret variable and fix a bug that was related to
its existence - the shadowing ret variable was assigned with -ETIMEDOUT
which was supposed to be retuned by the function, but was not because
the ret variable at the function scope was left intact.

Also remove the unneded goto unlock; jump (assigning the error code is
the last operation before unlocking the mutex anyway).

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>

Author: rlubos

subsys/net/ip/net_context.c

@@ -2170,8 +2170,6 @@ int net_context_recv(struct net_context *context,
 
 #if defined(CONFIG_NET_CONTEXT_SYNC_RECV)
 	if (!K_TIMEOUT_EQ(timeout, K_NO_WAIT)) {
-		int ret;
-
 		/* Make sure we have the lock, then the
 		 * net_context_packet_received() callback will release the
 		 * semaphore when data has been received.
@@ -2180,14 +2178,11 @@ int net_context_recv(struct net_context *context,
 
 		k_mutex_unlock(&context->lock);
 
-		ret = k_sem_take(&context->recv_data_wait, timeout);
-
-		k_mutex_lock(&context->lock, K_FOREVER);
-
-		if (ret == -EAGAIN) {
+		if (k_sem_take(&context->recv_data_wait, timeout) == -EAGAIN) {
 			ret = -ETIMEDOUT;
-			goto unlock;
 		}
+
+		k_mutex_lock(&context->lock, K_FOREVER);
 	}
 #endif /* CONFIG_NET_CONTEXT_SYNC_RECV */