x86, mce: add table driven machine check grading

The machine check grading (as in deciding what should be done for a given
register value) has to be done multiple times soon and it's also getting
more complicated.
So it makes sense to consolidate it into a single function. To get smaller
and more straight forward and possibly more extensible code I opted towards
a new table driven method. The various rules are put into a table
when is then executed by a very simple interpreter.

The grading engine is in a new file mce-severity.c. I also added a private
include file mce-internal.h, because mce.h is already a bit too cluttered.

This is dead code right now, but will be used in followon patches.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/cpu/mcheck/mce-internal.h

@@ -0,0 +1,10 @@
+#include <asm/mce.h>
+
+enum severity_level {
+	MCE_NO_SEVERITY,
+	MCE_SOME_SEVERITY,
+	MCE_UC_SEVERITY,
+	MCE_PANIC_SEVERITY,
+};
+
+int mce_severity(struct mce *a, int tolerant, char **msg);