[ACPI] fix IA64 build warning

Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLen Brown <len.brown@intelc.com>

include/asm-ia64/acpi-ext.h

@@ -11,6 +11,7 @@
 #define _ASM_IA64_ACPI_EXT_H
 
 #include <linux/types.h>
+#include <acpi/actypes.h>
 
 extern acpi_status hp_acpi_csr_space (acpi_handle, u64 *base, u64 *length);