arm920t: convert makefiles to Kbuild style

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/arch/arm/cpu/arm920t/at91/Makefile b/arch/arm/cpu/arm920t/at91/Makefile
index b2b1e56..561b4b4 100644
--- a/arch/arm/cpu/arm920t/at91/Makefile
+++ b/arch/arm/cpu/arm920t/at91/Makefile
@@ -5,30 +5,9 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-include $(TOPDIR)/config.mk
-
-LIB	= $(obj)lib$(SOC).o
-
-SOBJS	+= lowlevel_init.o
-COBJS	+= reset.o
-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))
-
-all:	$(obj).depend $(LIB)
-
-$(LIB):	$(OBJS)
-	$(call cmd_link_o_target, $(OBJS))
-
-#########################################################################
-
-# defines $(obj).depend target
-include $(SRCTREE)/rules.mk
-
-sinclude $(obj).depend
-
-#########################################################################
+obj-y	+= lowlevel_init.o
+obj-y	+= reset.o
+obj-y	+= timer.o
+obj-y	+= clock.o
+obj-y	+= cpu.o
+obj-y	+= at91rm9200_devices.o