Put SIM locked text in parenthesis

Changes how SIM locked text is assembled in CarrierTextController. The
text is put in parenthesis after the carrier name (or replaces it if the
carrier name is blank). This way, the locked text is easily associated
with the corresponding carrier name.

Test: visual
Fixes: 130857483

Change-Id: I86c5156907b2d245855f8be8158459c30c060495