Move AT91RM9200DK board support under board/atmel

We already have a vendor subdir for Atmel, so we should use it.

Signed-off-by: Haavard Skinnemoen <hskinnemoen <at> atmel.com>
diff --git a/Makefile b/Makefile
index ec8661a..1f63b8b 100644
--- a/Makefile
+++ b/Makefile
@@ -2302,7 +2302,7 @@
 xtract_omap730p2 = $(subst _cs0boot,,$(subst _cs3boot,, $(subst _config,,$1)))
 
 at91rm9200dk_config	:	unconfig
-	@$(MKCONFIG) $(@:_config=) arm arm920t at91rm9200dk NULL at91rm9200
+	@$(MKCONFIG) $(@:_config=) arm arm920t at91rm9200dk atmel at91rm9200
 
 cmc_pu2_config	:	unconfig
 	@$(MKCONFIG) $(@:_config=) arm arm920t cmc_pu2 NULL at91rm9200