mbigen: vtimer: disable vtimer mbigen probe when vtimer_irqbypass disabled

virt inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8ORX3



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Hardware firmware may have different implement, disable vtimer mbigen
probe when vtimer_irqbypass disabled.

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