[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/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index 78bc219..318787c 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -132,7 +132,7 @@
 #endif
 }
 
-#ifdef CONFIG_ACPI_BOOT
+#ifdef CONFIG_ACPI
 
 #define ACPI_MAX_PLATFORM_INTERRUPTS	256
 
@@ -917,4 +917,4 @@
 
 EXPORT_SYMBOL(acpi_unregister_ioapic);
 
-#endif				/* CONFIG_ACPI_BOOT */
+#endif				/* CONFIG_ACPI */