linaro/configs: rtsm: add virtio mmio support

Add support for the virtio mmio block device to the configs.  This also
requires a corresponding DTB change to also add the virtio device.

Signed-off-by: Ryan Harkin <ryan.harkin@linaro.org>
(cherry picked from commit f4ee755ffcb7fa4b716382d9c277f672612445df)
Signed-off-by: Alex Shi <alex.shi@linaro.org>
1 file changed