arm920t/at91: add clock.c

This patch adds an copy of arm926ejs/at91/clock.c to arm920t/at91. The
arm926ejs specialities are removed from arm920t version and vice versa.

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 5c71b77..8258ecd 100644
--- a/arch/arm/cpu/arm920t/at91/Makefile
+++ b/arch/arm/cpu/arm920t/at91/Makefile
@@ -28,6 +28,7 @@
 SOBJS	+= lowlevel_init.o
 COBJS	+= reset.o
 COBJS	+= timer.o
+COBJS	+= clock.o
 
 SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS))