base-files: ensure next boot just written kernel.

iopsys-brcm63xx-arm/base-files/lib/upgrade/broadcom-iopsys-5.sh

@@ -201,6 +201,7 @@ upgrade_commit() {
 	[ $VERBOSE -ge 1 ] && V="-V" || V=""
 
 	brcm_fw_tool $V -s $bankNext update $metaPath
+	brcm_fw_tool $V -u 0 set
 
 	# Read and possibly write "iVersion" in the nvram.
 	# Looks messy due to hex-string to integer conversion.