[OE-core][Patch v1] devicetree.bbclass: fix setting S

[max.oss.09@gmail.com]

From: Max Krummenacher <max.krummenacher@toradex.com>

When a user of devicetree.bbclass overrides setting S, e.g. to
git/overlays then having UNPACKDIR set to S results in that
git repo unpacked inside UNPACKDIR. Thus the sources are actually
in git/overlays/git/overlays rather than the expected git/overlays.

Change the logic, so that S by default is set to UNPACKDIR,
but a user can change S to point to were the sources actually
will be.

Fixes: 7a06069a041a ("devicetree.bbclass: switch away from S = WORKDIR")
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
---
 meta/classes-recipe/devicetree.bbclass | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/meta/classes-recipe/devicetree.bbclass b/meta/classes-recipe/devicetree.bbclass
index 1806cb62cbf7..e5dbd9a85714 100644
--- a/meta/classes-recipe/devicetree.bbclass
+++ b/meta/classes-recipe/devicetree.bbclass
@@ -40,8 +40,8 @@ PACKAGE_ARCH = "${MACHINE_ARCH}"
 SYSROOT_DIRS += "/boot/devicetree"
 FILES:${PN} = "/boot/devicetree/*.dtb /boot/devicetree/*.dtbo"
 
-S = "${WORKDIR}/sources"
-UNPACKDIR = "${S}"
+UNPACKDIR = "${WORKDIR}/sources"
+S = "${UNPACKDIR}"
 B = "${WORKDIR}/build"
 
 # Default kernel includes, these represent what are normally used for in-kernel
-- 
2.42.0