KVM: arm64: vgic-v3: Clearing pending status of vtimer on guest reset

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


CVE: NA

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On reset, userspace clears pending status for all PPIs and SGIs by
writing all 0's to GICR_ISPENDR0. The pending state of vtimer
interrupt is somehow staying in redistributor and we have to
explicitly clear it...

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