staging: unisys: visornic: prevent erroneous kfree of devdata pointer

staging: unisys: visornic: prevent erroneous kfree of devdata pointer

A struct visornic_devdata for each visornic device is actually allocated as
part of alloc_etherdev(), here in visornic_probe():

    netdev = alloc_etherdev(sizeof(struct visornic_devdata));

But code in devdata_release() was treating devdata as a pointer that needed
to be kfree()d!  This was causing all sorts of weird behavior after doing
an rmmod of visornic, both because free_netdev() was actually freeing the
memory used for devdata, and because devdata wasn't pointing to
dynamically-allocated memory in the first place.

The kfree(devdata) and the kref that tracked devdata's usage have been
appropriately deleted.

Signed-off-by: Tim Sell <Timothy.Sell@unisys.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>