hw/misc/aspeed_scu: Fix the revision ID cannot be set in the SOC layer for AST2700

hw/misc/aspeed_scu: Fix the revision ID cannot be set in the SOC layer for AST2700

According to the design of the AST2600, it has a Silicon Revision ID Register,
specifically SCU004 and SCU014, to set the Revision ID for the AST2600.
For the AST2600 A3, SCU004 is set to 0x05030303 and SCU014 is set to 0x05030303.
In the "aspeed_ast2600_scu_reset" function, the hardcoded value
"AST2600_A3_SILICON_REV" is set in SCU004, and "s->silicon_rev" is set in
SCU014. The value of "s->silicon_rev" is set by the SOC layer via the
"silicon-rev" property.

However, the design of the AST2700 is different. There are two SCU controllers:
SCU0 (CPU Die) and SCU1 (IO Die). In the AST2700, the firmware reads the SCU
Silicon Revision ID register (SCU0_000) and the SCUIO Silicon Revision ID
register (SCU1_000), combining them into a single 64-bit value.

The upper 32 bits represent the SCUIO, while the lower 32 bits correspond to the
SCU. For example, the AST2700-A1 revision is represented as 0x0601010306010103.
SCUIO_000 occupies bits [63:32] with a value of 0x06010103 and SCU_000 occupies
bits [31:0] with a value of 0x06010103.

Reference:
https://github.com/AspeedTech-BMC/u-boot/blob/aspeed-master-v2023.10/arch/arm/mach-aspeed/ast2700/cpu-info.c

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Tested-by: Nabih Estefan <nabihestefan@google.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250304064710.2128993-3-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>