Add description of all functions provided by Versatile Express
motherboard and daughterboards configuration controllers and
clock dependencies between devices.
Signed-off-by: NPawel Moll <pawel.moll@arm.com>

SMSC driver requires "vdd33a" and "vddvario" regulator supplies now.

Add fixed regulator describing 3V3 power line (in both motherboard's
Device Trees and the non-DT code) and force fixed regulator config
option if regulators framework is enabled.
Signed-off-by: NPawel Moll <pawel.moll@arm.com>

Signed-off-by: NPawel Moll <pawel.moll@arm.com>

This patch adds generic Versatile Express DT machine description,
Device Tree description for the motherboard and documentation for
the bindings.
Signed-off-by: NPawel Moll <pawel.moll@arm.com>