LoongArch: Enable PG when wakeup from suspend

Some firmwares don't enable PG when wakeup from suspend, so do it in
kernel. This can improve code compatibility for boot kernel.

Signed-off-by: Baoqi Zhang <zhangbaoqi@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

LoongArch: Add JUMP_VIRT_ADDR macro implementation to avoid using la.abs

Add JUMP_VIRT_ADDR macro implementation to avoid using la.abs directly.
This is a preparation for subsequent patches.

Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

LoongArch: Add suspend (ACPI S3) support

Add suspend (Suspend To RAM, aka ACPI S3) support for LoongArch.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>