crypto: sun8i-ss - Avoid -Wflex-array-member-not-at-end warning

crypto: sun8i-ss - Avoid -Wflex-array-member-not-at-end warning

-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Move the conflicting declaration to the end of the corresponding
structure. Notice that `struct ahash_request` is a flexible structure,
this is a structure that contains a flexible-array member.

With these changes fix the following warning:

drivers/crypto/allwinner/sun8i-ss/sun8i-ss.h:251:30: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>