--- zzzz-none-000/linux-4.1.52/arch/arm/boot/dts/Makefile	2018-05-28 02:26:45.000000000 +0000
+++ bcm63-7530ax-731/linux-4.1.52/arch/arm/boot/dts/Makefile	2022-03-02 11:37:12.000000000 +0000
@@ -662,5 +662,7 @@
 	mt8135-evbp1.dtb
 endif
 
+subdir-$(if $(CONFIG_BCM_CHIP_NUMBER),y) := brcm
+
 always		:= $(dtb-y)
 clean-files	:= *.dtb