nios2: use common rules to build built-in dtb

Using the common build support for built-in dtb files just requires
adding a .dtb.o target to obj-y.

This has the side effect that CONFIG_NIOS2_DTB_SOURCE should now be just
the dts filename in arch/nios2/boot/dts/ directory. Before any path was
supported, but if you want to build in your dtb to the kernel, it should
be in the kernel tree.

Cc: Ley Foon Tan <lftan@altera.com>
Cc: nios2-dev@lists.rocketboards.org
Signed-off-by: Rob Herring <robh@kernel.org>

1 files changed, 2 insertions, 4 deletions

diff --git a/arch/nios2/Makefile b/arch/nios2/Makefile
index 50eece1c6adb..db2e78fe65c7 100644
--- a/arch/nios2/Makefile
+++ b/arch/nios2/Makefile
@@ -49,16 +49,14 @@ BOOT_TARGETS = vmImage zImage
 PHONY += $(BOOT_TARGETS) install
 KBUILD_IMAGE := $(nios2-boot)/vmImage
 
-ifneq ($(CONFIG_NIOS2_DTB_SOURCE),"")
-        core-y  += $(nios2-boot)/
-endif
+core-y  += $(nios2-boot)/dts/
 
 all: vmImage
 
 archclean:
         $(Q)$(MAKE) $(clean)=$(nios2-boot)
 
-%.dtb: | scripts
+%.dtb %.dtb.S %.dtb.o: | scripts
         $(Q)$(MAKE) $(build)=$(nios2-boot)/dts $(nios2-boot)/dts/$@
 
 dtbs: