crypto: hisilicon - remove redundant assignment of pointer ctx

Pointer ctx is being re-assigned with the same value as it
was initialized with. The second assignment is redundant and
can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>