[ACPI] delete CONFIG_ACPI_BOOT

it has been a synonym for CONFIG_ACPI since 2.6.12

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index 6578f40..ebedd2e 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -2421,7 +2421,7 @@
                           ACPI-based IOAPIC Configuration
    -------------------------------------------------------------------------- */
 
-#ifdef CONFIG_ACPI_BOOT
+#ifdef CONFIG_ACPI
 
 int __init io_apic_get_unique_id (int ioapic, int apic_id)
 {
@@ -2574,4 +2574,4 @@
 	return 0;
 }
 
-#endif /*CONFIG_ACPI_BOOT*/
+#endif /* CONFIG_ACPI */