gpio: virtio: Add missing mailings lists in MAINTAINERS entry

Add gpio and virtualization lists in the MAINTAINERS entry for Virtio
gpio driver.

Reported-by: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>