MIPS: Add support for building device-tree binaries

Add a 'dtbs' Makefile target that just builds the device-tree binaries
enabled by the configuration.

Signed-off-by: Andrew Bresticker <[e-mail]>
Cc: Rob Herring <[e-mail]>
Cc: Pawel Moll <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Ian Campbell <[e-mail]>
Cc: Kumar Gala <[e-mail]>
Cc: James Hogan <[e-mail]>
Cc: Paul Burton <[e-mail]>
Cc: David Daney <[e-mail]>
Cc: John Crispin <[e-mail]>
Cc: Jayachandran C <[e-mail]>
Cc: Qais Yousef <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Patchwork: https://patchwork.linux-mips.org/patch/7557/
Signed-off-by: Ralf Baechle <[e-mail]>

arch/mips/Makefile

···
 %.dtb %.dtb.S %.dtb.o: | scripts
 	$(Q)$(MAKE) $(build)=arch/mips/boot/dts arch/mips/boot/dts/$@
 
+PHONY += dtbs
+dtbs: scripts
+	$(Q)$(MAKE) $(build)=arch/mips/boot/dts dtbs
+
 archprepare:
 ifdef CONFIG_MIPS32_N32
 	@echo '  Checking missing-syscalls for N32'
···
 	echo '  vmlinuz.srec         - SREC zboot image'
 	echo '  uImage               - U-Boot image'
 	echo '  uImage.gz            - U-Boot image (gzip)'
+	echo '  dtbs                 - Device-tree blobs for enabled boards'
 	echo
 	echo '  These will be default as appropriate for a configured platform.'
 endef

arch/mips/boot/.gitignore

···
 zImage.tmp
 calc_vmlinuz_load_addr
 uImage
+*.dtb

arch/mips/boot/dts/Makefile

···
 obj-y		+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
 
-clean-files	+= *.dtb.S
+targets		+= dtbs
+targets		+= $(dtb-y)
+
+dtbs: $(addprefix $(obj)/, $(dtb-y))
+
+clean-files	+= *.dtb *.dtb.S