nl80211: Add AP_VLAN interface to bridge after interface is up

nl80211: Add AP_VLAN interface to bridge after interface is up

In the current hostapd flow, AP_VLAN net device is added to a bridge
before the interface is brought up.

Interface up event is used in mac80211 layer for setting device context
in the driver. Vendor specific datapath offload configurations for net
device might also be set up in interface up event context. Adding
AP_VLAN interface to a bridge before the UP event could cause
inconsistent state for datapath offload context setup in a vendor
driver.

Change the sequence to add AP_VLAN interface to a bridge after the
interface is set up. This makes the interface up and bridge add sequence
for AP_VLAN to be consistent with that of a regular AP interface.

Signed-off-by: Radha Krishna Simha Jiguru <quic_rjiguru@quicinc.com>