powerpc/eeh: Fix /proc/ppc64/eeh creation

Since commit 188917e1, /proc/ppc64 is a
symlink to /proc/powerpc/. That means that creating /proc/ppc64/eeh will
end up with a unaccessible file, that is not listed under /proc/powerpc/
and, then, not listed under /proc/ppc64/.

Creating /proc/powerpc/eeh fixes that problem and maintain the
compatibility intended with the ppc64 symlink.
Signed-off-by: NThadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: <stable@kernel.org>	[3.x]

arch/powerpc/platforms/pseries/eeh.c

@@ -1338,7 +1338,7 @@ static const struct file_operations proc_eeh_operations = {
 static int __init eeh_init_proc(void)
 {
 	if (machine_is(pseries))
-		proc_create("ppc64/eeh", 0, NULL, &proc_eeh_operations);
+		proc_create("powerpc/eeh", 0, NULL, &proc_eeh_operations);
 	return 0;
 }
 __initcall(eeh_init_proc);