NFC: Add interface for offhost to associate to secure element

Add an interface for payment application to specify secure element, so
multiple secure elements are supported through Tap&Pay menu

Change-Id: If1548e12ccf5b06f032f5725315ad726a88d9002
CRs-Fixed: 744072
Modify isRoaming to getRoaming from Service state tracker.

Modify isRoaming method to getRoaming from Service state tracker
instead of phone object.

CRs-Fixed: 739327

Change-Id: I4ca0f6df65f38a3a0d64fde647fb8506347414c1