ARM: kirkwood: Cleanup comments in Sheevaplug dts files

Change the file names given in the comments of the Sheevaplug
dts files to actually match the real file names.

Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>