FROMLIST: virt: geniezone: Add irqfd support

irqfd enables other threads than vcpu threads to inject virtual
interrupt through irqfd asynchronously rather through ioctl interface.
This interface is necessary for VMM which creates separated thread for
IO handling or uses vhost devices.

Change-Id: I3a77cdcec0530193a518352f30c162d08b5b35ef
Signed-off-by: Yingshiuan Pan <yingshiuan.pan@mediatek.com>
Signed-off-by: Liju Chen <liju-clr.chen@mediatek.com>
Signed-off-by: Yi-De Wu <yi-de.wu@mediatek.com>
Bug: 280363874
Link: https://lore.kernel.org/lkml/20230727080005.14474-7-yi-de.wu@mediatek.com/