irda: irttp: fix memory leak in irttp_open_tsap() error path

Cleanup the memory we allocated earlier in irttp_open_tsap() when we hit
this error path. The leak goes back to at least 1da177e4
("Linux-2.6.12-rc2").

Discovered with Trinity (the syscall fuzzer).

Signed-off-by: Tommi Rantala <tt.rantala@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>