[sensors] Minor tuning of hal definition

  * Swap GEOMAGNETIC_FIELD with MAGNETIC_FIELD for more accurate
    definition.
  * Remove redundunt prefixes in various enum definitions.
  * Clarify that string type will be removed for well defined sensor
    types. This avoid dependency on strings defined in sensors.h.
  * Added SensorFlagShift enum.
  * Remove unused flag parameter in batch.
  * Remove legacy setDelay function.
  * Change the type of sensor flag to bitfield<SensorFlagBits>, and
    use uint32_t since only low 32 bits are used.

Test: all sensor works(in marlin), tested with sensorlogger.

Change-Id: I93a4d13c5d2e054857d1e400d15002aeb9a47368
diff --git a/sensors/1.0/default/Sensors.cpp b/sensors/1.0/default/Sensors.cpp
index f9f1ca6..8903397 100644
--- a/sensors/1.0/default/Sensors.cpp
+++ b/sensors/1.0/default/Sensors.cpp
@@ -142,15 +142,6 @@
                 enabled));
 }
 
-Return<Result> Sensors::setDelay(
-        int32_t sensor_handle, int64_t sampling_period_ns) {
-    return ResultFromStatus(
-            mSensorDevice->setDelay(
-                reinterpret_cast<sensors_poll_device_t *>(mSensorDevice),
-                sensor_handle,
-                sampling_period_ns));
-}
-
 Return<void> Sensors::poll(int32_t maxCount, poll_cb _hidl_cb) {
     hidl_vec<Event> out;
     hidl_vec<SensorInfo> dynamicSensorsAdded;
@@ -206,14 +197,13 @@
 
 Return<Result> Sensors::batch(
         int32_t sensor_handle,
-        int32_t flags,
         int64_t sampling_period_ns,
         int64_t max_report_latency_ns) {
     return ResultFromStatus(
             mSensorDevice->batch(
                 mSensorDevice,
                 sensor_handle,
-                flags,
+                0, /*flags*/
                 sampling_period_ns,
                 max_report_latency_ns));
 }