yuga: setup wpa_supplicant.conf

Push the initial wpa_supplicant.conf conf during system load, usually
the libhardware_legacy code will do this prior to starting
wpa_supplicant, since we're not yet allowing android to start
wpa_supplicant, we need to do this earlier.

Change-Id: I649f2ad9e1ed98634555cfa32551a452d453dfda