Make host-specific tools available to rauc

...so that it can exec `mksquashfs`, for example.

Change-Id: I4548b2d069512aa5e0208bf5f81cfaa596e07f94
diff --git a/package/czechlight-rauc/czechlight-rauc.mk b/package/czechlight-rauc/czechlight-rauc.mk
index 08a5b3b..6d3ef99 100644
--- a/package/czechlight-rauc/czechlight-rauc.mk
+++ b/package/czechlight-rauc/czechlight-rauc.mk
@@ -17,7 +17,7 @@
 	tar -cJf $(CZECHLIGHT_RAUC_TMP_TARGET_DIR)/cfg.tar.xz -T /dev/null
 	cp $(BR2_EXTERNAL_CZECHLIGHT_PATH)/package/czechlight-rauc/rauc-hook.sh $(CZECHLIGHT_RAUC_TMP_TARGET_DIR)/hook.sh
 
-	$(HOST_DIR)/usr/bin/rauc \
+	PATH=$(HOST_DIR)/bin:$(PATH) $(HOST_DIR)/bin/rauc \
 		--cert $(BR2_EXTERNAL_CZECHLIGHT_PATH)/crypto/rauc-cert.pem \
 		--key $(BR2_EXTERNAL_CZECHLIGHT_PATH)/crypto/rauc-key.pem \
 		bundle $(CZECHLIGHT_RAUC_TMP_TARGET_DIR) $(BINARIES_DIR)/update.raucb