scripts/Makefile.lib: Rework upstream_dtsi_include to get subdirectories

A problem with the logic in upstream_dtsi_include currently is that it
does not list directories such as dts/upstream/src/arm/nxp/imx and so
will not findi "imx6ul-pinfunc.h" for example as it is normally and
correctly included without vendor sub-paths. Expand the current wildcard
glob to catch these directories too.

Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index e89a4a5..ac14e4f 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -205,8 +205,10 @@
 # Modified for U-Boot
 upstream_dtsi_include = $(addprefix -I, $(srctree)/dts/upstream/src/ \
 	$(sort $(dir $(wildcard $(srctree)/dts/upstream/src/$(ARCH)/*/*))) \
+	$(sort $(dir $(wildcard $(srctree)/dts/upstream/src/$(ARCH)/*/*/*))) \
 	$(if (CONFIG_ARM64), \
-		 $(sort $(dir $(wildcard $(srctree)/dts/upstream/src/arm64/*/*)))))
+		 $(sort $(dir $(wildcard $(srctree)/dts/upstream/src/arm64/*/*))) \
+		 $(sort $(dir $(wildcard $(srctree)/dts/upstream/src/arm64/*/*/*)))))
 dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
 		 $(UBOOTINCLUDE)                                         \
 		 -I$(dir $<)                                             \