board: add support for ARM Juno r0 and r1 Development Boards

The Juno ARM Development Platform (ADP) is a software development
platform for ARMv8-A, it includes the Juno Versatile Express board
and an ARMv8-A reference software port available through Linaro.

Signed-off-by: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>