board: samsung: refactor host programs

Some Samsung boards have their own tools under board/samsung/<board>/tools/.
This commit refactor more makefiles with "hostprogs-y".

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/board/samsung/smdkv310/Makefile b/board/samsung/smdkv310/Makefile
index dbc621b..9e37b4e 100644
--- a/board/samsung/smdkv310/Makefile
+++ b/board/samsung/smdkv310/Makefile
@@ -4,16 +4,9 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-ifndef CONFIG_SPL_BUILD
-obj-y	+= smdkv310.o
-endif
-
-ifdef CONFIG_SPL_BUILD
-all: $(OBJTREE)/tools/mk$(BOARD)spl
-endif
-
-# Fix ME after we implement hostprogs-y.
 ifdef CONFIG_SPL_BUILD
-$(OBJTREE)/tools/mk$(BOARD)spl:	tools/mkv310_image.c
-	$(HOSTCC) tools/mkv310_image.c -o $(OBJTREE)/tools/mk$(BOARD)spl
+hostprogs-y := tools/mksmdkv310spl
+always := $(hostprogs-y)
+else
+obj-y	+= smdkv310.o
 endif