Convert docs/specs/virt-ctlr.txt to rST format.
I added the name of the device to give readers a bit more idea
of which device we're actually documenting here.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20230927151205.70930-7-peter.maydell@linaro.org
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
