ci: Set BR2_DL_DIR & BR2_CCACHE_DIR

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
diff --git a/ci/build-all-defconfigs.sh b/ci/build-all-defconfigs.sh
index f8b1cd4..92db788 100755
--- a/ci/build-all-defconfigs.sh
+++ b/ci/build-all-defconfigs.sh
@@ -30,6 +30,11 @@
 shopt -s expand_aliases
 source op-build-env
 
+if [ -n "$DL_DIR" ]; then
+	unset BR2_DL_DIR
+	export BR2_DL_DIR=${DL_DIR}
+fi
+
 for i in ${DEFCONFIGS[@]}; do
         op-build $i
         echo 'BR2_CCACHE=y' >> output/.config