arm920t/at91: add at91rm9200_devices.c

This is a copy of arm926ejs/at91 api for perpherial initialisation.
At the moment we just need the usart part of the api.

Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/arch/arm/cpu/arm920t/at91/Makefile b/arch/arm/cpu/arm920t/at91/Makefile
index 4417dfe..309bcd6 100644
--- a/arch/arm/cpu/arm920t/at91/Makefile
+++ b/arch/arm/cpu/arm920t/at91/Makefile
@@ -30,6 +30,7 @@
 COBJS	+= timer.o
 COBJS	+= clock.o
 COBJS	+= cpu.o
+COBJS	+= at91rm9200_devices.o
 
 SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS))