tests/net: Put the context down and not only the tcp part in tcp2 test

This will clean up the context properly and call net_tcp_put()
relevantly.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
diff --git a/tests/net/tcp2/src/main.c b/tests/net/tcp2/src/main.c
index 183da82..e5e656f 100644
--- a/tests/net/tcp2/src/main.c
+++ b/tests/net/tcp2/src/main.c
@@ -559,7 +559,7 @@
 	/* Peer will release the semaphone after it sends ACK for data */
 	test_sem_take(K_MSEC(100), __LINE__);
 
-	net_tcp_put(ctx);
+	net_context_put(ctx);
 
 	/* Peer will release the semaphone after it receives
 	 * proper ACK to FIN | ACK
@@ -621,7 +621,7 @@
 	/* Peer will release the semaphone after it sends ACK for data */
 	test_sem_take(K_MSEC(100), __LINE__);
 
-	net_tcp_put(ctx);
+	net_context_put(ctx);
 
 	/* Peer will release the semaphone after it receives
 	 * proper ACK to FIN | ACK