docs: driver-api: virtio: slightly reword virtqueues allocation paragraph

"It's at this stage that" means "At this point", so use the latter as it
is more effective.

Signed-off-by: Bagas Sanjaya <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Michael S. Tsirkin <[e-mail]>

Documentation/driver-api/virtio/virtio.rst

···
 for a driver in the bus that can handle the device and call that
 driver's ``probe`` method.
 
-It's at this stage that the virtqueues will be allocated and configured
-by calling the appropriate ``virtio_find`` helper function, such as
-virtio_find_single_vq() or virtio_find_vqs(), which will end up
-calling a transport-specific ``find_vqs`` method.
+At this point, the virtqueues will be allocated and configured by
+calling the appropriate ``virtio_find`` helper function, such as
+virtio_find_single_vq() or virtio_find_vqs(), which will end up calling
+a transport-specific ``find_vqs`` method.
 
 
 References