ACPICA: Add support for 64 bit loong_arch compilation

ACPICA commit d809b69cf43c632c8fe5b42372a891216fdd9223

Add 64 bit loong_arch architecture by defining ACPI_MACHINE_WIDTH to 64.
Useful for acpica tools and incorporating ACPICA into the Firmware Test
Suite.

Link: https://github.com/acpica/acpica/commit/d809b69c


Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>