treewide: consolidate upgrade state set

Set the (sys)upgrade state when sourcing the stage2 script instead of
setting the state for each target individual.

This change fixes the, due to a missing state set, not working upgrade
led on ath79 and apm821xx.

Signed-off-by: Mathias Kresin <dev@kresin.me>

target/linux/ramips/base-files/lib/upgrade/platform.sh

@@ -367,9 +367,3 @@ platform_do_upgrade() {
 		;;
 	esac
 }
-
-blink_led() {
-	. /etc/diag.sh; set_state upgrade
-}
-
-append sysupgrade_pre_upgrade blink_led