The "phone" icon that you had means you have a missed call. If you don't have any missed calls, you'll only see the signal strength.
If you want that icon back, just don't pick up the next phone call while you're in the car.
'14 528-xdrive - daily driver/winter beater, '06 Boxster - for fun, '07 M6- for even more fun. '16 435 on order