Settings: Fix carrier/sim slot string logic for msim settings

Original change: http://review.cyanogenmod.org/#/c/74670/
Original author: cretin45 <cretin45@gmail.com>

Change-Id: Ieaf660ec3b937ea7dd26394be343c439fbdfbd80
Settings: Disable mobile network switch if MSIM

Original change: http://review.cyanogenmod.org/#/c/74455/
Original author: cretin45 <cretin45@gmail.com>

Change-Id: Ia676e31eefec3c90cc7e501f4e4766adaaf2955d