brcm63xx: upgrade-bundle: Log upgrade environment vars

Just to show that sysupgrade environment vars
are reachable in upgrade bundle.

refs #7306

iopsys-brcm63xx-arm/image/upgrade-bundle/upgrade

@@ -12,11 +12,17 @@ log() {
 do_pre_upgrade() {
 	local image=$1
 	log "- pre_upgrade -"
+# Log below left for informative and further use.
+# UPGRADE_OPT_ variables set by sysupgrade should be visible here.
+	log "Upgrade options: " $(env | grep -E '^UPGRADE_OPT')
 }
 
 do_post_upgrade() {
 	local image=$1
 	log "- post_upgrade -"
+# Log below left for informative and further use. 
+# UPGRADE_OPT_ variables set by sysupgrade should be visible here.
+	log "Upgrade options: " $(env | grep -E '^UPGRADE_OPT')
 }
 
 case $invocation in