dm: core: Add livetree address functions

Add functions to access addresses in the device tree. These are brought
in from Linux 4.10.

Also fix up the header guard for fdtaddr.h to avoid confusion.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/Makefile b/drivers/core/Makefile
index c25288e..1c6795a 100644
--- a/drivers/core/Makefile
+++ b/drivers/core/Makefile
@@ -11,5 +11,5 @@
 obj-$(CONFIG_DM)	+= dump.o
 obj-$(CONFIG_$(SPL_)REGMAP)	+= regmap.o
 obj-$(CONFIG_$(SPL_)SYSCON)	+= syscon-uclass.o
-obj-$(CONFIG_OF_LIVE) += of_access.o
+obj-$(CONFIG_OF_LIVE) += of_access.o of_addr.o
 obj-$(CONFIG_OF_CONTROL) += ofnode.o