sdm: Avoid looping over event data list when registering events

When an event is supported, array index to fd is initialized in
InitializePollFd(). Take advantage of this index during registration
instead of looping over event data list again.

Change-Id: Ieaafab185152aef3b30ee53aaaf542bede353390
CRs-Fixed: 2277063
2 files changed