powerpc/4xx: Move machine_check_4xx() into platforms/4xx

Now that we have 4xx platform directory we can move the 4xx machine
check handler in there. Again we drop get_mc_reason() and replace it
with regs->dsisr directly (which is actually SPRN_ESR).

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 69b54ab..8d1f79b 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -428,23 +428,7 @@
 #define clear_single_step(regs)	((regs)->msr &= ~MSR_SE)
 #endif
 
-#if defined(CONFIG_4xx)
-int machine_check_4xx(struct pt_regs *regs)
-{
-	unsigned long reason = get_mc_reason(regs);
-
-	if (reason & ESR_IMCP) {
-		printk("Instruction");
-		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
-	} else
-		printk("Data");
-	printk(" machine check in kernel mode.\n");
-
-	return 0;
-}
-
-
-#elif defined(CONFIG_E500)
+#if defined(CONFIG_E500)
 int machine_check_e500mc(struct pt_regs *regs)
 {
 	unsigned long mcsr = mfspr(SPRN_MCSR);