selftests: net: add tcp_inq to gitignore

sha: 702353b5 ("selftest: add test for TCP_INQ") forgot to add
tcp_inq to .gitignore.
Signed-off-by: NAnders Roxell <anders.roxell@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tools/testing/selftests/net/.gitignore

@@ -12,3 +12,4 @@ tcp_mmap
 udpgso
 udpgso_bench_rx
 udpgso_bench_tx
+tcp_inq