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>

arch/powerpc/platforms/4xx/Makefile

@@ -1,4 +1,4 @@
-obj-y				+= uic.o
+obj-y				+= uic.o machine_check.o
 obj-$(CONFIG_PPC4xx_OCM)	+= ocm.o
 obj-$(CONFIG_4xx_SOC)		+= soc.o
 obj-$(CONFIG_PCI)		+= pci.o

arch/powerpc/platforms/4xx/machine_check.c

@@ -0,0 +1,26 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <linux/ptrace.h>
+
+#include <asm/reg.h>
+
+int machine_check_4xx(struct pt_regs *regs)
+{
+	unsigned long reason = regs->dsisr;
+
+	if (reason & ESR_IMCP) {
+		printk("Instruction");
+		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
+	} else
+		printk("Data");
+	printk(" machine check in kernel mode.\n");
+
+	return 0;
+}