aspeed: Add Supermicro X11 SPI machine type

aspeed: Add Supermicro X11 SPI machine type

supermicrox11-bmc is configured with ast2400-a1 SoC. This does not match
the Supermicro documentation for X11 BMCs, and it does not match the
devicetree file in the Linux kernel.

As it turns out, some Supermicro X11 motherboards use AST2400 SoCs,
while others use AST2500.

Introduce new machine type supermicrox11-spi-bmc with AST2500 SoC
to match the devicetree description in the Linux kernel. Hardware
configuration details for this machine type are guesswork and taken
from defaults as well as from the Linux kernel devicetree file.

The new machine type was tested with aspeed-bmc-supermicro-x11spi.dts
from the Linux kernel and with Linux versions 6.0.3 and 6.1-rc2.
Linux booted successfully from initrd and from both SPI interfaces.
Ethernet interfaces were confirmed to be operational.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20221025165109.1226001-1-linux@roeck-us.net
[ clg: Renamed machine to 'supermicro-x11spi-bmc' ]
Message-Id: <20221025165109.1226001-1-linux@roeck-us.net>
Signed-off-by: Cédric Le Goater <clg@kaod.org>