hw/arm/aspeed: Rename IRQ table and machine name for AST2700 A0

hw/arm/aspeed: Rename IRQ table and machine name for AST2700 A0

Currently, AST2700 SoC only supports A0. To support AST2700 A1, rename its IRQ
table and machine name.

To follow the machine deprecation rule, the initial machine "ast2700-evb" is
aliased to "ast2700a0-evb." In the future, we will alias "ast2700-evb" to new
SoCs, such as "ast2700a1-evb."

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250307035945.3698802-9-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>