[ImuCal] Changes log-level for LoadAshCalibration fail message

- This change aims to reduce confusion with this log message since it
  is frequently not an error and arises when there is no previous cal
  data to load (e.g., on first device boot).
- This change was migrated from Google3 (284259994).

Bug: 145825423
Test: Built firmware.
Change-Id: I919a858f920b06eab657df40d4b7947953e42a0b
diff --git a/firmware/os/algos/calibration/nano_calibration/nano_calibration.cc b/firmware/os/algos/calibration/nano_calibration/nano_calibration.cc
index 0471b8d..feabbd6 100644
--- a/firmware/os/algos/calibration/nano_calibration/nano_calibration.cc
+++ b/firmware/os/algos/calibration/nano_calibration/nano_calibration.cc
@@ -334,7 +334,9 @@
       }
     }
   } else {
-    NANO_CAL_LOGE(sensor_tag, "ASH failed to recall calibration data.");
+    // This is not necessarily an error since there may not be any previously
+    // stored runtime calibration data to load yet (e.g., first device boot).
+    NANO_CAL_LOGW(sensor_tag, "ASH did not recall calibration data.");
   }
 
   return false;