x86: fix arch/x86/kernel/setup.c build warning when !CONFIG_X86_RESERVE_LOW_64K

Impact: cleanup

Fix:

  arch/x86/kernel/setup.c:592: warning: 'dmi_low_memory_corruption' defined but not used

this is only used if CONFIG_X86_RESERVE_LOW_64K is defined.
Signed-off-by: NRichard A. Holden III <aciddeath@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/setup.c

@@ -587,6 +587,7 @@ static struct x86_quirks default_x86_quirks __initdata;
 
 struct x86_quirks *x86_quirks __initdata = &default_x86_quirks;
 
+#ifdef CONFIG_X86_RESERVE_LOW_64K
 static int __init dmi_low_memory_corruption(const struct dmi_system_id *d)
 {
 	printk(KERN_NOTICE
@@ -598,6 +599,7 @@ static int __init dmi_low_memory_corruption(const struct dmi_system_id *d)
 
 	return 0;
 }
+#endif
 
 /* List of systems that have known low memory corruption BIOS problems */
 static struct dmi_system_id __initdata bad_bios_dmi_table[] = {