coccinelle: api: update kzfree script to kfree_sensitive

Commit 453431a5

 ("mm, treewide: rename kzfree() to kfree_sensitive()")
renames kzfree to kfree_sensitive and uses memzero_explicit(...) instead of
memset(..., 0, ...) internally. Update cocci script to reflect these
changes.

Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>