use acpi.h include instead of manually adding acpi_slp_type.

Change-Id: I2a3aaf10e453fa6cce8a993356f2a0587178209a
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/276
Tested-by: build bot (Jenkins)
Reviewed-by: Uwe Hermann <uwe@hermann-uwe.de>
diff --git a/src/northbridge/intel/i945/northbridge.c b/src/northbridge/intel/i945/northbridge.c
index dfe4fe7..a10bb4a 100644
--- a/src/northbridge/intel/i945/northbridge.c
+++ b/src/northbridge/intel/i945/northbridge.c
@@ -29,6 +29,7 @@
 #include <bitops.h>
 #include <cpu/cpu.h>
 #include <boot/tables.h>
+#include <arch/acpi.h>
 #include "chip.h"
 #include "i945.h"
 
@@ -252,8 +253,6 @@
 }
 
 #if CONFIG_HAVE_ACPI_RESUME
-extern u8 acpi_slp_type;
-
 static void northbridge_init(struct device *dev)
 {
 	switch (pci_read_config32(dev, SKPAD)) {