ARM: Kirkwood: Remove kirkwood_defconfig

This is no longer needed now that kirkwood lives inside mach-mvebu.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lkml.kernel.org/r/1405028192-9623-3-git-send-email-andrew@lunn.ch


Signed-off-by: Jason Cooper <jason@lakedaemon.net>