x86: Replace ARCH_SETUP by a proper x86_init_ops

ARCH_SETUP is a horrible leftover from the old arch/i386 mach support
code. It still has a lonely user in xen. Move it to x86_init_ops.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/x86_init.c

@@ -42,4 +42,8 @@ struct __initdata x86_init_ops x86_init = {
 		.intr_init		= native_init_IRQ,
 		.trap_init		= x86_init_noop,
 	},
+
+	.oem = {
+		.arch_setup		= x86_init_noop,
+	},
 };