hostapd(hidl): Add helper functions for writing config file

The HIDL interface for hostapd is a wrapper used to create hostapd conf file.
This file will be then be passed to the hostapd core to avoid
duplication of the conf parsing.

Note: This is a port of the methods in HostapdManager.

Bug: 36646171
Test: Compiles with CONFIG_CTRL_IFACE_HIDL=y in android.config
Change-Id: If11e3f795c05f34442566343ae02bc2a385890a6
3 files changed