at91: Add esd gmbh OTC570 board support

This patch adds support for esd gmbh OTC570 board.
The OTC570 is based on an Atmel AT91SAM9263 SoC.

Signed-off-by: Daniel Gorsulowski <Daniel.Gorsulowski@esd.eu>
diff --git a/Makefile b/Makefile
index e4431f7..c4402c2 100644
--- a/Makefile
+++ b/Makefile
@@ -2870,6 +2870,9 @@
 	fi;
 	@$(MKCONFIG) -a at91sam9m10g45ek arm arm926ejs at91sam9m10g45ek atmel at91
 
+otc570_config	:	unconfig
+	@$(MKCONFIG) $(@:_config=) arm arm926ejs otc570 esd at91
+
 pm9263_config	:	unconfig
 	@$(MKCONFIG) $(@:_config=) arm arm926ejs pm9263 ronetix at91