meta-ampere: rsyslog: support IPMI SEL

Enable rsyslog to save IPMI SEL event into /var/log/ipmi_sel.

Tested:
1. Log IPMI SEL event using xyz.openbmc_project.Logging.IPMI
2. Check /var/log/ipmi_sel for the new entry
 root@mtjade:~# cat /var/log/ipmi_sel
 2021-09-01T09:23:49.022943+00:00 1,c0,3ACD000FEB00000000000000,,,

Signed-off-by: Thang Q. Nguyen <thang@os.amperecomputing.com>
Change-Id: Ic02a6166498251ed1e84a56e4847f465a069c872