scripts: Makefile: Add multi overlay dtbo-base apply verify

Current board device tree overlay verify only support
single soc device tree dtb. Add support overlay apply verify
for multi soc device tree dtb in dtbo-base.

Change-Id: Idca1c57969303f701be37550da23c117cbd90470
Signed-off-by: Maria Yu <[email protected]>

Author: sixtaku

Diff for: scripts/Makefile.dtbo

@@ -10,7 +10,12 @@ dtbo	:= $(addprefix $(obj)/,$(dtbo))
 ifneq ($(DTC_OVERLAY_TEST_EXT),)
 DTC_OVERLAY_TEST = $(DTC_OVERLAY_TEST_EXT)
 quiet_cmd_dtbo_verify	= VERIFY  $@
-cmd_dtbo_verify = $(DTC_OVERLAY_TEST) $(addprefix $(obj)/,$($(@F)-base)) $@ $(dot-target).tmp
+cmd_dtbo_verify = $(foreach m,\
+	$(addprefix $(obj)/,$($(@F)-base)),\
+		$(if $(m),\
+			$(DTC_OVERLAY_TEST) $(m) $@ \
+			$(dot-target).$(patsubst $(obj)/%.dtb,%,$(m)).tmp;))\
+			true
 else
 cmd_dtbo_verify = true
 endif