KVM: arm64: arch_timer: Probe vtimer irqbypass capability

virt inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8K89F


CVE: NA

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HiSilicon implementation of GICv4.1 has provided direct injection
capability of vtimer interrupts. Enable vtimer-irqbypass in KVM
depends on:
- HW support at mbigen level
- HW support at GIC level
- in_kernel irqchip support
- set "kvm-arm.vtimer_irqbypass=1" in the command line

Once vtimer-irqbypass is enabled, there's no need to use the vtimer
forwarded irq inject.

Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Haibin Wang <wanghaibin.wang@huawei.com>
Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
Signed-off-by: Dongxu Sun <sundongxu3@huawei.com>