MIPS: Loongson-3: Move chipset ACPI code from drivers to arch

SB700/SB710/SB800 chipset ACPI code is mostly Loongson-3 specific
routines rather than a "platform driver".

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <sjhill@realitydiluted.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11273/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>