crypto: talitos - fix bad kfree

Fix a kfree to an invalid address which causes an oops when running
on SEC v2.0 h/w (introduced in commit 702331b "crypto: talitos - add
hmac algorithms").

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>