Fixed deadlock in IccSmsInterfaceManager

The sync call in to RIL should run on a different thread than
IccSmsInterfaceManager's handler thread, otherwise it will
cause deadlock because the RIL response to unlock is also
running on the same thread.

Test: Manual boot up to make sure no ANR occurs.
Bug: 148923425
Change-Id: I1f59f8af2134fb5e8b205dec0f728b29e24cbe5f
Merged-In: I1f59f8af2134fb5e8b205dec0f728b29e24cbe5f