crypto: tcrypt - Fix leak of struct aead_request in test_aead_speed()

Fix leakage of memory for struct aead_request that is allocated via
aead_request_alloc() but not released via aead_request_free().
Reported by Coverity - CID 1163869.

Signed-off-by: Christian Engelmayer <cengelma@gmx.at>
Reviewed-by: Marek Vasut <marex@denx.de>
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>