board: ti: convert makefiles to Kbuild style

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Tom Rini <trini@ti.com>
diff --git a/board/ti/dra7xx/Makefile b/board/ti/dra7xx/Makefile
index e558f4c..434e8d1 100644
--- a/board/ti/dra7xx/Makefile
+++ b/board/ti/dra7xx/Makefile
@@ -5,29 +5,4 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-include $(TOPDIR)/config.mk
-
-LIB	= $(obj)lib$(BOARD).o
-
-COBJS	:= evm.o
-
-SRCS	:= $(COBJS:.o=.c)
-OBJS	:= $(addprefix $(obj),$(COBJS))
-
-$(LIB):	$(obj).depend $(OBJS)
-	$(call cmd_link_o_target, $(OBJS))
-
-clean:
-	rm -f $(OBJS)
-
-distclean:	clean
-	rm -f $(LIB) core *.bak $(obj).depend
-
-#########################################################################
-
-# defines $(obj).depend target
-include $(SRCTREE)/rules.mk
-
-sinclude $(obj).depend
-
-#########################################################################
+obj-y	:= evm.o