MIPS: dts: Avoid unneeded built-in.a in DTS dirs

arch/mips/boot/dts/Makefile collects objects from sub-directories into
built-in.a only when CONFIG_BUILTIN_DTB is enabled. Reflect it also to
the sub-directory Makefiles. This suppresses unneeded built-in.a
creation in arch/mips/boot/dts/*/ directories.

While I am here, I replaced $(patsubst %.dtb, %.dtb.o, $(dtb-y)) with
$(addsuffix .o, $(dtb-y)) to simplify the code a little bit.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/19099/
Signed-off-by: James Hogan <jhogan@kernel.org>

arch/mips/boot/dts/brcm/Makefile

@@ -34,4 +34,4 @@ dtb-$(CONFIG_DT_NONE) += \
 	bcm97425svmb.dtb \
 	bcm97435svmb.dtb
 
-obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
+obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))

arch/mips/boot/dts/cavium-octeon/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 dtb-$(CONFIG_CAVIUM_OCTEON_SOC)	+= octeon_3xxx.dtb octeon_68xx.dtb
 
-obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
+obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))

arch/mips/boot/dts/ingenic/Makefile

@@ -3,4 +3,4 @@ dtb-$(CONFIG_JZ4740_QI_LB60)	+= qi_lb60.dtb
 dtb-$(CONFIG_JZ4770_GCW0)	+= gcw0.dtb
 dtb-$(CONFIG_JZ4780_CI20)	+= ci20.dtb
 
-obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
+obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))

arch/mips/boot/dts/lantiq/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 dtb-$(CONFIG_DT_EASY50712)	+= easy50712.dtb
 
-obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
+obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))

arch/mips/boot/dts/mscc/Makefile

@@ -1,3 +1,3 @@
 dtb-$(CONFIG_LEGACY_BOARD_OCELOT)	+= ocelot_pcb123.dtb
 
-obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
+obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))

arch/mips/boot/dts/mti/Makefile

@@ -2,4 +2,4 @@
 dtb-$(CONFIG_MIPS_MALTA)	+= malta.dtb
 dtb-$(CONFIG_LEGACY_BOARD_SEAD3)	+= sead3.dtb
 
-obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
+obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))

arch/mips/boot/dts/netlogic/Makefile

@@ -5,4 +5,4 @@ dtb-$(CONFIG_DT_XLP_FVP)	+= xlp_fvp.dtb
 dtb-$(CONFIG_DT_XLP_GVP)	+= xlp_gvp.dtb
 dtb-$(CONFIG_DT_XLP_RVP)	+= xlp_rvp.dtb
 
-obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
+obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))

arch/mips/boot/dts/pic32/Makefile

@@ -4,4 +4,4 @@ dtb-$(CONFIG_DTB_PIC32_MZDA_SK)		+= pic32mzda_sk.dtb
 dtb-$(CONFIG_DTB_PIC32_NONE)		+= \
 					pic32mzda_sk.dtb
 
-obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
+obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))

arch/mips/boot/dts/ralink/Makefile

@@ -6,4 +6,4 @@ dtb-$(CONFIG_DTB_MT7620A_EVAL)	+= mt7620a_eval.dtb
 dtb-$(CONFIG_DTB_OMEGA2P)	+= omega2p.dtb
 dtb-$(CONFIG_DTB_VOCORE2)	+= vocore2.dtb
 
-obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
+obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))

arch/mips/boot/dts/xilfpga/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 dtb-$(CONFIG_FIT_IMAGE_FDT_XILFPGA)	+= nexys4ddr.dtb
 
-obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
+obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))