SystemUI: Fix mobile data will turn on automatically issue

When turn off data service by data switch shortcut, the state of
'Settings.Global.MOBILE_DATA' for each subscription is not updated. As a
result, data service will turn on when click data switch shortcut again.

When change global mobile data state, update 'Settings.Global.MOBILE_DATA'
for each subscription at the same time.

CRs-Fixed: 678603

Change-Id: Ia1ab07e03bedd9faea7ef44f1f00f7a7736245de