MMS: The sound file name disppear after wake up UE

It will clear the element and removeEventListener of
SMIL_DOCUMENT_END_EVENT when activity onPause().

Add eventListener in onResume(). Because it will be removed
in onPause() and only delete the element when this activity
finish.

CRs-Fixed: 397577

Change-Id: Ic0603312a133339c120570bf3ef8fe8276715729