[sensors] Add parameter check to poll()

Check maxCount parameter so that it will not allocate overly large
amount of memory if input parameter is bad.

Bug: 32953589
Test: build and pass vts
Change-Id: Ia19e0315ab1623b8b6580889c1e058a19e6c9670
diff --git a/sensors/1.0/default/Sensors.cpp b/sensors/1.0/default/Sensors.cpp
index 8903397..e4ef99d 100644
--- a/sensors/1.0/default/Sensors.cpp
+++ b/sensors/1.0/default/Sensors.cpp
@@ -151,12 +151,13 @@
         return Void();
     }
 
-    std::unique_ptr<sensors_event_t[]> data(new sensors_event_t[maxCount]);
+    int bufferSize = maxCount <= kPollMaxBufferSize ? maxCount : kPollMaxBufferSize;
+
+    std::unique_ptr<sensors_event_t[]> data(new sensors_event_t[bufferSize]);
 
     int err = mSensorDevice->poll(
             reinterpret_cast<sensors_poll_device_t *>(mSensorDevice),
-            data.get(),
-            maxCount);
+            data.get(), bufferSize);
 
     if (err < 0) {
         _hidl_cb(ResultFromStatus(err), out, dynamicSensorsAdded);