ARM: config: Add a multi_v5_defconfig

To allow regression build testing of multi v5 systems, add a
multi_v5_defconfig, similar to the multi_v7_defconfig. This is based
on kirkwood_defconfig, but with a few other boards added which claim
to be MULTI_v5.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>