arm: mvebu: Avoid generating kwbimage.cfg in the source tree

At present some boards generate kwbimage.cfg in the source tree
during the build. This breaks buildman testing on some systems
where the source tree is read-only. Update makefile rules to
generate it in the build tree instead.

Note some other boards have the kwbimage.cfg file written in
advance, hence we need check if the file exists in the build
tree first, otherwise we fall back to one in the source tree.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/board/Marvell/db-88f6281-bp/Makefile b/board/Marvell/db-88f6281-bp/Makefile
index e6aa7e3..003e9f6 100644
--- a/board/Marvell/db-88f6281-bp/Makefile
+++ b/board/Marvell/db-88f6281-bp/Makefile
@@ -4,9 +4,9 @@
 extra-y := kwbimage.cfg
 
 quiet_cmd_sed = SED     $@
-      cmd_sed = sed $(SEDFLAGS_$(@F)) $< >$(dir $<)$(@F)
+      cmd_sed = sed $(SEDFLAGS_$(@F)) $< >$(dir $@)$(@F)
 
 SEDFLAGS_kwbimage.cfg = -e "s/^\#@BOOT_FROM.*/BOOT_FROM	$(if $(CONFIG_CMD_NAND),nand,spi)/"
-$(src)/kwbimage.cfg: $(src)/kwbimage.cfg.in include/autoconf.mk \
+$(obj)/kwbimage.cfg: $(src)/kwbimage.cfg.in include/autoconf.mk \
 		include/config/auto.conf
 	$(call if_changed,sed)
diff --git a/board/Marvell/db-xc3-24g4xg/Makefile b/board/Marvell/db-xc3-24g4xg/Makefile
index 4dd5790..24e8200 100644
--- a/board/Marvell/db-xc3-24g4xg/Makefile
+++ b/board/Marvell/db-xc3-24g4xg/Makefile
@@ -6,9 +6,9 @@
 extra-y	:= kwbimage.cfg
 
 quiet_cmd_sed = SED     $@
-      cmd_sed = sed $(SEDFLAGS_$(@F)) $< >$(dir $<)$(@F)
+      cmd_sed = sed $(SEDFLAGS_$(@F)) $< >$(dir $@)$(@F)
 
 SEDFLAGS_kwbimage.cfg =-e "s|^BINARY.*|BINARY $(srctree)/$(@D)/binary.0 0000005b 00000068|"
-$(src)/kwbimage.cfg: $(src)/kwbimage.cfg.in include/autoconf.mk \
+$(obj)/kwbimage.cfg: $(src)/kwbimage.cfg.in include/autoconf.mk \
 		include/config/auto.conf
 	  $(call if_changed,sed)
diff --git a/board/mikrotik/crs305-1g-4s/Makefile b/board/mikrotik/crs305-1g-4s/Makefile
index 895331b..c03f534 100644
--- a/board/mikrotik/crs305-1g-4s/Makefile
+++ b/board/mikrotik/crs305-1g-4s/Makefile
@@ -6,9 +6,9 @@
 extra-y	:= kwbimage.cfg
 
 quiet_cmd_sed = SED     $@
-      cmd_sed = sed $(SEDFLAGS_$(@F)) $< >$(dir $<)$(@F)
+      cmd_sed = sed $(SEDFLAGS_$(@F)) $< >$(dir $@)$(@F)
 
 SEDFLAGS_kwbimage.cfg =-e "s|^BINARY.*|BINARY $(srctree)/$(@D)/binary.0 0000005b 00000068|"
-$(src)/kwbimage.cfg: $(src)/kwbimage.cfg.in include/autoconf.mk \
+$(obj)/kwbimage.cfg: $(src)/kwbimage.cfg.in include/autoconf.mk \
 		include/config/auto.conf
 	  $(call if_changed,sed)