USB: serial: kl5kusb105: fix memleak on open

commit 3f203f057edfcf6bd02c6b942799262bfcf31f73 upstream.

Fix memory leak of control-message transfer buffer on successful open().

Fixes: 6774d5f53271 ("USB: serial: kl5kusb105: fix open error path")
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>