Re-enable out of tree device trees

This snippet was mistakenly removed with 8ef9fee.

Note that this isn't a matter of policy, it simply enables
the option to do it.  The in-tree device tree is still the default.

This enables things like workbook or schematic generated device
trees.  It also addresses the inevitable fact that the upstream kernel
will probably not want device trees for every board in the world.

Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/common/recipes-kernel/linux/linux-obmc_4.4.bb b/common/recipes-kernel/linux/linux-obmc_4.4.bb
index 24cde9f..945b43d 100644
--- a/common/recipes-kernel/linux/linux-obmc_4.4.bb
+++ b/common/recipes-kernel/linux/linux-obmc_4.4.bb
@@ -18,3 +18,13 @@
 
 inherit kernel
 require recipes-kernel/linux/linux-yocto.inc
+
+do_patch_append() {
+        for DTB in "${KERNEL_DEVICETREE}"; do
+               DT=`basename ${DTB} .dtb`
+                if [ -r "${WORKDIR}/${DT}.dts" ]; then
+                        cp ${WORKDIR}/${DT}.dts \
+                                ${STAGING_KERNEL_DIR}/arch/${ARCH}/boot/dts
+               fi
+       done
+}