Add p2p_go_max_inactivity config option

Add p2p_go_max_inactivity config option

This enables setting a different max inactivity timeout for P2P GO.
This timeout is used to detect inactive clients. In some scenarios
it may be useful to have control over this and set a shorter timeout
than the default 300s. For example when running STA and P2P GO interfaces
concurrently, the STA interface may perform scans which may cause the
GO to miss a disassoc / deauth frames from a client and keep assuming
that the client is connected until the inactivity detection kicks in.
300 secs is a bit too long for such scenarios and creates a bad user
experience.

Signed-hostap: Eyal Shapira <eyal@wizery.com>