uboot-phytec

ARM: mx6: Enable STDIO deregistering on Novena

Novena supports USB keyboard, which is a pluggable device and can be
unplugged. Thus, we need to be able to deregister it's stdio device.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>