DT: Vendor: Add prefixes used by Kirkwood devices

Add a number of vendor prefixes by kirkwood devices. These are not all
stock tickers, but have been in use for a while so changing would not
be easy.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Rob Herring <robh@kernel.org>