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
3 files changed