x86, realmode: Unbreak the ia64 build of drivers/acpi/sleep.c

Revert usage of acpi_wakeup_address and move definition
to x86 architecture code in order to make compilation work
in ia64.

[jsakkine: tested compilation in ia64/x86-64 and added
proper commit message]

Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Originally-by: H. Peter Anvin <hpa@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1338370421-27735-1-git-send-email-jarkko.sakkinen@intel.com
Cc: Tony Luck <tony.luck@intel.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index ebaa045..74ee4ab 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -25,8 +25,6 @@
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 
-#include <asm/realmode.h>
-
 #include "internal.h"
 #include "sleep.h"
 
@@ -93,13 +91,11 @@
 static int acpi_sleep_prepare(u32 acpi_state)
 {
 #ifdef CONFIG_ACPI_SLEEP
-	unsigned long wakeup_pa = real_mode_header->wakeup_start;
 	/* do we have a wakeup address for S2 and S3? */
 	if (acpi_state == ACPI_STATE_S3) {
-		if (!wakeup_pa)
+		if (!acpi_wakeup_address)
 			return -EFAULT;
-		acpi_set_firmware_waking_vector(
-				(acpi_physical_address)wakeup_pa);
+		acpi_set_firmware_waking_vector(acpi_wakeup_address);
 
 	}
 	ACPI_FLUSH_CPU_CACHE();