oem-ampere: eventManager: Fix DIMMx_Status sensor IDs checking

DIMMx_Status sensor IDs have format `4 + 2x` with x from 0 to 23.

Signed-off-by: Thu Nguyen <thu@os.amperecomputing.com>
Change-Id: Iea8219e005a2773e288920b6aaa529b6f5d43de4
diff --git a/oem/ampere/event/oem_event_manager.hpp b/oem/ampere/event/oem_event_manager.hpp
index 521a16b..54f9cdd 100644
--- a/oem/ampere/event/oem_event_manager.hpp
+++ b/oem/ampere/event/oem_event_manager.hpp
@@ -280,6 +280,15 @@
      */
     std::string dimmIdxsToString(uint32_t dimmIdxs);
 
+    /** @brief Convert sensor ID to DIMM index. Return maxDIMMInstantNum
+     * in failure.
+     *
+     *  @param[in] sensorId - sensorID
+     *
+     *  @return uint8_t - DIMM index
+     */
+    uint8_t sensorIdToDIMMIdx(const uint16_t& sensorId);
+
     /** @brief Convert the DIMM training failure into logging string.
      *
      *  @param[in] failureInfo - the one-hot DIMM index byte