mbigen: Sets the regs related to vtimer irqbypass

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


CVE: NA

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According to the HiSilicon chip manual, two registers need to be
set for each die to enable vtimer irqbypass. These regs are used
to change the vtimer interrupts reporting channel. Therefore, KVM
must enable vtimer irqbypass once the regs are set. Use
kvm-arm.vtimer_irqbypass to control whether vtimer irqbypass is
enabled.

According to the bios settings, each device connected to mbigen
device will cause mbigen_device_probe to be executed. But
vtimer_mbigen_device_probe only needs to be executed once. Add
a check to determine whether the vtimer_mbigen_device has been
executed.

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