Handle interface disabled/enabled more consistently

Handle interface disabled/enabled more consistently

It was possible for the interface not to be marked in INTERFACE_DISABLED
state in case the event was processed for P2P GO because the wpa_s
instance could have been removed in case of a separate group interface.
Change the state first to avoid leaving different state for the case
where separate group interface is not used.

Mark scan to be a normal scan on INTERFACE_ENABLED so that scanning
rules (e.g., skip scan if no networks enabled) get used consistently.

Signed-off-by: Jouni Malinen <j@w1.fi>