ATF mvebu is required for building a functional bootloader for A7K/A8K and
A37xx platforms. uDPU device is added as the first target.

A3700 platform has a wide range of settings which can be used per device, so
options are defined under the Device sections.

Platform also required WTP (recovery) tools and mv-ddr package for the DDR
topology configuration. 32-bit cross compiler is used for building the WTMI
image.

After the build, flash-image.bin can be used with the bubt command from the
u-boot shell to flash the new version of u-boot.

Signed-off-by: Vladimir Vid <vladimir.vid@sartura.hr>