arm64: Add config switch and kernel parameter for CPU0 hotplug

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8RJPO


CVE: NA

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New config switch CONFIG_ARM64_BOOTPARAM_HOTPLUG_CPU0 sets whether
default state of arm64_cpu0_hotpluggable is on or off.

If the config switch is off, arm64_cpu0_hotpluggable is off
by default. But arm64_cpu0_hotpluggable can still be turned on
by kernel parameter arm64_cpu0_hotplug at boot.

If the config switch is on, arm64_cpu0_hotpluggable is always on.

whether CPU0 is hotpluggable depends on cpu_can_disable(0) and
arm64_cpu0_hotpluggable.

The default value of the config switch is off.

Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>