fix: ci: DTS file list missing space

On concat to DTS list from DTSI, a space was missing.

Signed-off-by: Jorge Marques <[email protected]>

Author: gastmaier

ci/build.sh

@@ -396,7 +396,7 @@ compile_devicetree() {
 		done <<< "$dtsi_files"
 	fi
 
-	dts_files+=$(echo "$files" | grep ^arch/$ARCH/boot/dts/ | grep dts$ || true)
+	dts_files+=\ $(echo "$files" | grep ^arch/$ARCH/boot/dts/ | grep dts$ || true)
 	if [[ -z "$dts_files" ]]; then
 		echo "no dts on range, skipped"
 		return $err