scripts/dtc: Add yamltree.c to dtc sources

dtc has a new source file, yamltree.c, that needs to be copied when
syncing dtc sources.
Signed-off-by: NRob Herring <robh@kernel.org>

scripts/dtc/update-dtc-source.sh

@@ -32,7 +32,7 @@ DTC_UPSTREAM_PATH=`pwd`/../dtc
 DTC_LINUX_PATH=`pwd`/scripts/dtc
 
 DTC_SOURCE="checks.c data.c dtc.c dtc.h flattree.c fstree.c livetree.c srcpos.c \
-		srcpos.h treesource.c util.c util.h version_gen.h Makefile.dtc \
+		srcpos.h treesource.c util.c util.h version_gen.h yamltree.c Makefile.dtc \
 		dtc-lexer.l dtc-parser.y"
 LIBFDT_SOURCE="Makefile.libfdt fdt.c fdt.h fdt_addresses.c fdt_empty_tree.c \
 		fdt_overlay.c fdt_ro.c fdt_rw.c fdt_strerror.c fdt_sw.c \