mctp: test: Use NULL macros

Replace the PTR_EQ NULL checks wit the NULL macros. More idiomatic and
specific.
Acked-by: Daniel Latypov <dlatypov@google.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Acked-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

net/mctp/test/route-test.c

@@ -361,7 +361,7 @@ static void mctp_test_route_input_sk(struct kunit *test)
 	} else {
 		KUNIT_EXPECT_NE(test, rc, 0);
 		skb2 = skb_recv_datagram(sock->sk, 0, 1, &rc);
-		KUNIT_EXPECT_PTR_EQ(test, skb2, NULL);
+		KUNIT_EXPECT_NULL(test, skb2);
 	}
 
 	__mctp_route_test_fini(test, dev, rt, sock);
@@ -431,7 +431,7 @@ static void mctp_test_route_input_sk_reasm(struct kunit *test)
 		skb_free_datagram(sock->sk, skb2);
 
 	} else {
-		KUNIT_EXPECT_PTR_EQ(test, skb2, NULL);
+		KUNIT_EXPECT_NULL(test, skb2);
 	}
 
 	__mctp_route_test_fini(test, dev, rt, sock);