sel: Add OEM SEL Record data structure

The code only supports SEL Event Records. Re-define the data structure
to use union to support different kinds of SEL records:
* SEL Event Records
* OEM SEL Record, type C0-DF
* OEM SEL Record, type E0-FF

Signed-off-by: Lei YU <yulei.sh@bytedance.com>
Change-Id: I7cf69c3e1d47664815c029308a52c62049c8e691
diff --git a/storagehandler.cpp b/storagehandler.cpp
index 74e5d65..3f09940 100644
--- a/storagehandler.cpp
+++ b/storagehandler.cpp
@@ -263,7 +263,8 @@
                     sizeof(record.nextRecordID));
         std::memcpy(static_cast<uint8_t*>(response) +
                         sizeof(record.nextRecordID),
-                    &record.recordID + requestData->offset, readLength);
+                    &record.event.eventRecord.recordID + requestData->offset,
+                    readLength);
         *data_len = sizeof(record.nextRecordID) + readLength;
     }