arm: mvebu: add button for OpenBlocks AX3-4

The OpenBlocks AX3-4 board has one software-controlled button on the
front side, labeled "INIT", so we add minimal support for this button
in the kernel.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
1 file changed