net/irda/mcs7780: fix memory leaks in mcs_net_open()

If rx_urb allocation fails in mcs_setup_urbs(), tx_urb leaks.
If mcs_receive_start() fails in mcs_net_open(), the both urbs are not deallocated.

The patch fixes the issues and by the way fixes label indentation.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>