gpio: virtio: remove timeout

The driver imposes an arbitrary one second timeout on virtio requests,
but the specification doesn't prevent the virtio device from taking
longer to process requests, so remove this timeout to support all
systems and device implementations.

Fixes: 3a29355a

 ("gpio: Add virtio-gpio driver")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>