[POWERPC] Reworking machine check handling and Fix 440/440A

This adds a cputable function pointer for the CPU-side machine
check handling. The semantic is still the same as the old one,
the one in ppc_md. overrides the one in cputable, though
ultimately we'll want to change that so the CPU gets first.

This removes CONFIG_440A which was a problem for multiplatform
kernels and instead fixes up the IVOR at runtime from a setup_cpu
function. The "A" version of the machine check also tweaks the
regs->trap value to differenciate the 2 versions at the C level.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
diff --git a/include/asm-ppc/reg_booke.h b/include/asm-ppc/reg_booke.h
index 4cad45a..2f1a2af 100644
--- a/include/asm-ppc/reg_booke.h
+++ b/include/asm-ppc/reg_booke.h
@@ -207,7 +207,7 @@
 #define	CCR1_TCS	0x00000080 /* Timer Clock Select */
 
 /* Bit definitions for the MCSR. */
-#ifdef CONFIG_440A
+#ifdef CONFIG_4xx
 #define MCSR_MCS	0x80000000 /* Machine Check Summary */
 #define MCSR_IB		0x40000000 /* Instruction PLB Error */
 #define MCSR_DRB	0x20000000 /* Data Read PLB Error */