SensorService now always clamps the requested rate

Requested rate will be clamped to the minimum rate and then
to 1ms. Previously we would return an error if a lower
rate was asked. The SensorManager documentation wording
allows this change.

We do this to get more consistancy between all the sensor
drivers / HALs

Change-Id: I199f76486fb76ccbb11e7280460a03726c767e84

Author: pixelflinger

services/sensorservice/SensorService.cpp

@@ -478,8 +478,9 @@ status_t SensorService::setEventRate(const sp<SensorEventConnection>& connection
     if (ns < 0)
         return BAD_VALUE;
 
-    if (ns == 0) {
-        ns = sensor->getSensor().getMinDelayNs();
+    nsecs_t minDelayNs = sensor->getSensor().getMinDelayNs();
+    if (ns < minDelayNs) {
+        ns = minDelayNs;
     }
 
     if (ns < MINIMUM_EVENTS_PERIOD)