xtensa-build-zephyr: download rimage later, just before needed

This helps catch hidden rimage dependencies.

Signed-off-by: Marc Herbert <marc.herbert@intel.com>

scripts/xtensa-build-zephyr.sh

@@ -219,6 +219,8 @@ build_all()
 			       -l "$STAGING"/sof/sof-"$platform".ldc \
 			       "$bdir"/zephyr/zephyr.elf
 
+			download_missing_submodules
+
 			# Build rimage
 			RIMAGE_DIR=build-rimage
 			cmake -B "$RIMAGE_DIR" -S modules/audio/sof/rimage
@@ -370,8 +372,6 @@ see https://docs.zephyrproject.org/latest/getting_started/index.html"
 		ln -s "$SOF_TOP" "${WEST_TOP}"/modules/audio/sof
 	}
 
-	download_missing_submodules
-
 	test "${#PLATFORMS[@]}" -eq 0 || build_all
 }