libmems: Remove warning of missing Trigger in IioDeviceImpl

BUG=b:176459004
TEST=builds

Change-Id: I6fb3219f3c6579762fad36ea2064ef510e4b3200
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/2606181
Reviewed-by: Cheng-Hao Yang <chenghaoyang@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Cheng-Hao Yang <chenghaoyang@chromium.org>
Commit-Queue: Cheng-Hao Yang <chenghaoyang@chromium.org>
diff --git a/libmems/iio_device_impl.cc b/libmems/iio_device_impl.cc
index 75e20ea..00c3c2e 100644
--- a/libmems/iio_device_impl.cc
+++ b/libmems/iio_device_impl.cc
@@ -201,10 +201,8 @@
 IioDevice* IioDeviceImpl::GetTrigger() {
   const iio_device* trigger;
   int error = iio_device_get_trigger(device_, &trigger);
-  if (error) {
-    LOG(WARNING) << log_prefix_ << "Unable to get trigger";
+  if (error)
     return nullptr;
-  }
 
   if (trigger == nullptr)
     return nullptr;