hw/misc/aspeed_hace: Rename R_HASH_DEST to R_HASH_DIGEST and introduce 64-bit hash...

hw/misc/aspeed_hace: Rename R_HASH_DEST to R_HASH_DIGEST and introduce 64-bit hash digest address helper

Renaming R_HASH_DEST to R_HASH_DIGEST for better semantic clarity.

The AST2700 CPU, based on the Cortex-A35, features a 64-bit DRAM address space.
To prepare for future AST2700 support, this change introduces a new helper
function hash_get_digest_addr() to encapsulate digest address extraction logic
and improve code readability.

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250515081008.583578-11-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>