The abbreviation of severity should be SEV instead of SER, so the CPER
severity constants are renamed accordingly. GHES severity constants
are renamed in the same way too.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>