ARM: at91: remove references to RM9200DK

The AT91 RM9200DK board was removed long time ago.
Remove existing references that were not cleaned up.

Fixes: 1c85752258 ("ARM: remove broken "at91rm9200dk" board")
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
2 files changed