SystemUI: Don't refresh mobile label for non-data SubId

In dsds mode, it didn't judge whether it is default data SubId or not when
refreshing views, it would refresh mobile label view whichever the phone
id is. so it is shown sometimes that SIM2 chosen as data connection within
main drop-down status bar, although SIM1 has been set successfully.

Don't refresh mobile label view when it's not default data SubId.

CRs-Fixed: 811645
Change-Id: I8c05fd3a2ee25d5046ac7d7b64dac140cc1c444a