spkm3: remove bad kfree, unnecessary export

We're kfree()'ing something that was allocated on the stack!

Also remove an unnecessary symbol export while we're at it.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>