irqchip/gic-v4.1: Detect ITS vtimer interrupt bypass capability

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


CVE: NA

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According to Hisilicon spec, using GITS_VERSION(0xC000) bit[12] to
indicate ITS vtimer interrupt bypass capability.

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