base-files: bring up vlan interface too

Vlan subinterface was never brought up when using vlan-based preinit network.
Tested forcing ifname="" before preinit_ip() on a Tp-Link Archer C5v4.

Signed-off-by: Luiz Angelo Daros de Luca <[email protected]>

package/base-files/files/lib/preinit/10_indicate_preinit

@@ -18,6 +18,9 @@ preinit_ip_config() {
 	fi
 
 	ip link set dev $netdev up
+	if [ -n "$vid" ]; then
+		ip link set dev $1 up
+	fi
 	ip -4 address add $pi_ip/$pi_netmask broadcast $pi_broadcast dev $1
 }