hw/loongarch/virt: Fix big endian support with MCFG table

hw/loongarch/virt: Fix big endian support with MCFG table

With API build_mcfg(), it is not necessary with parameter structure
AcpiMcfgInfo to convert to little endian since it is directly used
with host native endian.

Here remove endian conversion before calling function build_mcfg().
With this patch, bios-tables-test passes to run on big endian host
machine S390.

Fixes: 735143f10d3e ("hw/loongarch: Add acpi ged support")
Cc: qemu-stable@nongnu.org
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20250604065502.1114098-2-maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>