crypto: ccp - memset request context to zero during import

Since a crypto_ahash_import() can be called against a request context
that has not had a crypto_ahash_init() performed, the request context
needs to be cleared to insure there is no random data present. If not,
the random data can result in a kernel oops during crypto_ahash_update().

Cc: <stable@vger.kernel.org> # 3.14.x-
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>