hw/gpio/aspeed_sgpio: Add basic device model for Aspeed SGPIO

This initial implementation includes the basic device structure,
memory-mapped register definitions, and read/write handlers for the
SGPIO control registers.

Signed-off-by: Yubin Zou <yubinz@google.com>
Reviewed-by: Kane Chen <kane_chen@aspeedtech.com>
Link: https://lore.kernel.org/qemu-devel/20251219-aspeed-sgpio-v5-1-fd5593178144@google.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
3 files changed