ramips: mt7621: print size of factory initramfs-image if it's too big

It's helpful to know the current and maximal size of the imagefiles if the
creation fails.

Signed-off-by: Sven Roederer <devel-sven@geroedel.de>

target/linux/ramips/image/mt7621.mk

@@ -26,7 +26,7 @@ define Build/iodata-factory
 		mv $(factory_bin).new $(factory_bin); \
 		$(CP) $(factory_bin) $(BIN_DIR)/; \
 	else \
-		echo "WARNING: initramfs kernel image too big, cannot generate factory image" >&2; \
+		echo "WARNING: initramfs kernel image too big, cannot generate factory image (actual $$(stat -c%s $@); max $(fw_size))" >&2; \
 	fi
 endef
 
@@ -66,7 +66,7 @@ define Build/ubnt-erx-factory-image
 		\
 		$(CP) $(1) $(BIN_DIR)/; \
 	else \
-		echo "WARNING: initramfs kernel image too big, cannot generate factory image" >&2; \
+		echo "WARNING: initramfs kernel image too big, cannot generate factory image (actual $$(stat -c%s $@); max $(KERNEL_SIZE))" >&2; \
 	fi
 endef