staging: vt6655: Fix memory leak in wpa_ioctl()

Fix a memory leak in the wpa_ioctl() error handling path so that 'param' is
also freed correctly in case of an unsupported ioctl.
Detected by Coverity: CID 144380.

Signed-off-by: Christian Engelmayer <cengelma@gmx.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>