add getPreferredDataSubId to SubscriptionManager
and rename setPreferredData -> serPreferredDataSubId

Bug: 117833883
Test: sanity
Change-Id: I67b18f1ef450c3d9e5615b3d2ec8a53a0691d7af
Merged-In: I67b18f1ef450c3d9e5615b3d2ec8a53a0691d7af
5 files changed