LoongArch: Set CPU#0 as the io master for FDT

mainline inclusion
from mainline-v6.5-rc1
commit 872b368b
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7MWTU


CVE: NA

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ACPI systems set io masters by parsing ACPI MADT, FDT systems have no
MADT so we explicitly set CPU#0 as the io master. Otherwise CPU#0 will
be considered as hotpluggable.

Signed-off-by: Yongzhen Zhang <zhangyongzhen@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>