Input: sidewinder - fix memory leak

In sw_connect we leak 'buf' and 'idbuf' when we do not leave via one of
the fail* labels. This was spotted by the coverity checker.

Patch is compile tested only due to lack of hardware.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>