Since `VirtIO` is not the official notation,
unify the name to `VIRTIO`.
In the text, `Virtio` and `virtio` can also be used
depending on the context.
Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>
Add VirtIO Entropy driver.
The `virtio,device4` is a somewhat unfamiliar naming convention,
but it follows the convention used in Linux.
Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>