net/irda: add missing error path release_sock call

This makes sure that release_sock is called for all error conditions in
irda_getsockopt.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Brad Spengler <spender@grsecurity.net>
Cc: stable@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>