hw/arm/virt-acpi-build.c: Migrate SPCR creation to common location

hw/arm/virt-acpi-build.c: Migrate SPCR creation to common location

RISC-V should also generate the SPCR in a manner similar to ARM.
Therefore, instead of replicating the code, relocate this function
to the common AML build.

Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240129021440.17640-2-jeeheng.sia@starfivetech.com>
[ Changes by AF:
 - Add missing Language SPCR entry
]
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>