hw/arm/aspeed_ast27x0 Introduce vbootrom memory region

hw/arm/aspeed_ast27x0 Introduce vbootrom memory region

Introduce a new vbootrom memory region. The region is mapped at address
"0x00000000" and has a size of 128KB, identical to the SRAM region size.
This memory region is intended for loading a vbootrom image file as part of the
boot process.

The vbootrom registered in the SoC's address space using the ASPEED_DEV_VBOOTROM
index.

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Reviewed-by: Nabih Estefan <nabihestefan@google.com>
Tested-by: Nabih Estefan <nabihestefan@google.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250424075135.3715128-2-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>