crypto: ccree - use devm_kzalloc() for hash data

As the lifetime of the hash data matches the lifetime of the driver,
hash data can be allocated using the managed allocators.
While at it, simplify cc_hash_free() by removing an unneeded check
(hash_handle is always valid here).

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>