Removed redundant gravity events
GRAVITY_BASE_DATA_SET and GRAVITY_EVENT_RAW_DATA_REPORT_ON_TIME were the same
GRAVITY_BASE_DATA_SET has been removed.
GRAVITY_BASE_DATA_SET was used for polling events and GRAVITY_EVENT_RAW_DATA_REPORT_ON_TIME was used for event driven
Since both these represent the same gravity sensor event, DATA_SET type has been removed.
And GRAVITY_EVENT_RAW_DATA_REPORT_ON_TIME has been renamed to GRAVITY_RAW_DATA_EVENT to make it simpler.
The change has been tested on rd-pq device for all sensord API and all API were found to be working.
Change-Id: I224d0ccfd8b4e48c132a357f410028d6a1cfe7de