virtio-net: Fix vq->use_event_idx flag check

VIRTIO_RING_F_EVENT_IDX is a bit position value, but
virtio_init_device_vq populates vq->use_event_idx by ANDing this value
directly to vdev->features.

Fix the check for this flag in virtio_init_device_vq.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Tu Dinh Ngoc <dinhngoc.tu@irit.fr>
Link: https://lore.kernel.org/r/20220929121858.156-1-dinhngoc.tu@irit.fr
Signed-off-by: Will Deacon <will@kernel.org>
diff --git a/virtio/core.c b/virtio/core.c
index f432421..ea0e5b6 100644
--- a/virtio/core.c
+++ b/virtio/core.c
@@ -165,7 +165,7 @@
 	struct vring_addr *addr = &vq->vring_addr;
 
 	vq->endian		= vdev->endian;
-	vq->use_event_idx	= (vdev->features & VIRTIO_RING_F_EVENT_IDX);
+	vq->use_event_idx	= (vdev->features & (1UL << VIRTIO_RING_F_EVENT_IDX));
 	vq->enabled		= true;
 
 	if (addr->legacy) {