ramips: allow JCG_MAXSIZE in kiB in Build/jcg-header

This allows JCG_MAXSIZE to be specified in kilobytes. This makes
this value more consistent and easier comparable with other size
variables.

This also changes the only occurence of the variable, for Cudy WR1000.

This is backported to 19.07 for convenience, as other developers
backporting device support might not be aware that JCG_MAXSIZE in
kilobytes would not work there.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
(cherry picked from commit 0bf4d681d4)

target/linux/ramips/image/Makefile

@@ -48,7 +48,9 @@ define Device/seama
 endef
 
 define Build/jcg-header
-	$(STAGING_DIR_HOST)/bin/jcgimage -v $(1) $(if $(JCG_MAXSIZE), -m $(JCG_MAXSIZE),) -u $@ -o $@.new
+	$(STAGING_DIR_HOST)/bin/jcgimage -v $(1) \
+		$(if $(JCG_MAXSIZE), -m $$(($(subst k, * 1024,$(JCG_MAXSIZE)))),) \
+		-u $@ -o $@.new
 	mv $@.new $@
 endef
 

target/linux/ramips/image/mt76x8.mk

@@ -33,7 +33,7 @@ define Device/cudy_wr1000
   IMAGES += factory.bin
   IMAGE/factory.bin := \
         $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | jcg-header 92.122
-  JCG_MAXSIZE := 8060928
+  JCG_MAXSIZE := 7872k
   DEVICE_TITLE := Cudy WR1000
   DEVICE_PACKAGES := kmod-mt76x2
   SUPPORTED_DEVICES += wr1000