MIPS: Loongson64: Select ARCH_MIGHT_HAVE_PC_SERIO

Commit 7a407aa5 ("MIPS: Push ARCH_MIGHT_HAVE_PC_SERIO down to
platform level") moves the global MIPS ARCH_MIGHT_HAVE_PC_SERIO select
down to various platforms, but doesn't add it to Loongson64 platforms
which need it, so add the selects to these platforms too.

Fixes: 7a407aa5 ("MIPS: Push ARCH_MIGHT_HAVE_PC_SERIO down to platform level")
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18704/


Signed-off-by: James Hogan <jhogan@kernel.org>