crypto: sun8i-ss - remove redundant memzero_explicit()

Remove redundant memzero_explicit() in sun8i_ss_cipher() before calling
kfree_sensitive(). kfree_sensitive() will zero the memory with
memzero_explicit().

Fixes: 453431a5

 ("mm, treewide: rename kzfree() to kfree_sensitive()")
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>