bmi3: fixed the mysterious "mute on first call" bug When UI-enabled fw boots on a previously blank (no /mmi/* files) FFS for the first time, the output_volume member of the persistent UI settings structure was left uninitialized, corresponding to the earpiece volume being set to mute, which is an invalid setting. Because of other quirks in the far-from-finished UI code, this volume setting takes effect only when the first call is answered, producing the odd behaviour seen at the user level. The current fix is to set the blank-FFS default for output_volume to volume level 4, which is the same -6 dB Iota volume as the ACI default.