[][openwrt-24][common][bsp][Enable updating feeds with rebase for unified autobuild]

[Description]
Add support to enable rebase on updating feeds for unified autobuild

[Release-log]
N/A

Change-Id: Ia5aca0966551cc459c84a13f94455a573ab1454c
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/9620157
diff --git a/autobuild/unified/rules b/autobuild/unified/rules
index 29f4e2a..45477bb 100755
--- a/autobuild/unified/rules
+++ b/autobuild/unified/rules
@@ -164,7 +164,7 @@
 }
 
 update_feeds() {
-	exec_log "${openwrt_root}/scripts/feeds update -a"
+	exec_log "${openwrt_root}/scripts/feeds update -a -r -s"
 
 	mtk_feed_path=${openwrt_root}/feeds/mtk_openwrt_feed
 }