toradex: common: Add sysinfo driver

This commit introduces support for the Toradex sysinfo driver in U-Boot,
which uses information from Toradex config block to print correct
board model.
In case the Toradex config block is not present sysinfo prints the model
of the board provided by device tree removing per board specific prints.

Signed-off-by: Emanuele Ghidoli <emanuele.ghidoli@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>