x86, mce, severity: Cleanup severity table

The current format of an item in this table is:
  condition(param, ..., level, message [, condition2 ...])

So we have to check both an item's head and tail to find the conditions
which match the item.

Format them in a more straight forward manner:
  item(level, message, condition [, condition2 ...])

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/4DEED61F.5010502@jp.fujitsu.com
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>