Settings: Fix up Sound tile if device doesn't have vibrator

The sound tile doesn't work properly on non-vibrator device until user check corresponding mode.

This patch will fix that issue, force Silent and Sound mode enabled by default and remove sound
mode preference so that user can't edit it.

PS8 : Remove Sound modes preference on non-vibrator device
PS9 : Remove unneeded updateSummary()
PS10: Remove unneeded block
PS11: Cleanup
PS12: Update commit message

Change-Id: I6f29a5b4590f9ab959e2164920afa0f8fe621656