The coverity checker spotted that this was a NULL pointer dereference in
the "if (copy_from_user(...))" case since the next step is to
kfree(cache->filled_head).

There's no need to free cache at this point, and it's getting free'd
later.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NJody McIntyre <scjody@modernduck.com>