Sensors: MultiHal: ignore errors from poll calls

MultiHal was not properly fielding errors from the poll() calls of
sub-HALs.  Propagating errors received from sub-HALs up to Sensor
Services causes Sensor Services to abort, so instead of propagating
the error up to Sensor Services, the MultiHal logs a message to
logcat to fix the sub-HAL problem.

Bug: 30060537
Change-Id: I6e20c193a2f2d228da48cf3d5a23e439eaf663df
diff --git a/modules/sensors/multihal.cpp b/modules/sensors/multihal.cpp
index 0edbc2d..7044551 100644
--- a/modules/sensors/multihal.cpp
+++ b/modules/sensors/multihal.cpp
@@ -155,7 +155,11 @@
         ALOGV("writerTask before poll() - bufferSize = %d", bufferSize);
         eventsPolled = device->poll(device, buffer, bufferSize);
         ALOGV("writerTask poll() got %d events.", eventsPolled);
-        if (eventsPolled == 0) {
+        if (eventsPolled <= 0) {
+            if (eventsPolled < 0) {
+                ALOGV("writerTask ignored error %d from %s", eventsPolled, device->common.module->name);
+                ALOGE("ERROR: Fix %s so it does not return error from poll()", device->common.module->name);
+            }
             continue;
         }
         pthread_mutex_lock(&queue_mutex);