running with multiple SoCs compiled in very well anyway, so this just
wastes space. As more and more SoCs arrive in the tree, it is better
to edit one master file that builds them all than many board files.
Create a new option for at91rm9200 support. Set this option in
std.at91. Create a new option for the at91sam9 standard devices. Set
this option in std.at91sam9. Retire files.at91sam9. Add options for
at91sam9x25 SoC and SAM9X25EK board, but don't connect it just yet as
the supporting files aren't quite ready.
Note: device at91rm9200 and device at91sam9 are presently mutually
exclusive.
