crypto: inside-secure - fix zeroing of the request in ahash_exit_inv

A request is zeroed in safexcel_ahash_exit_inv(). This request total
size is EIP197_AHASH_REQ_SIZE while the memset zeroing it uses
sizeof(struct ahash_request), which happens to be less than
EIP197_AHASH_REQ_SIZE. This patch fixes it.

Fixes: f6beaea3 ("crypto: inside-secure - authenc(hmac(sha256), cbc(aes)) support")
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>