x86: fix long standing bug with usb after hibernation with 4GB ram

aperture_64.c takes a piece of memory and makes it into iommu
window... but such window may not be saved by swsusp -- that leads to
oops during hibernation.
Signed-off-by: NPavel Machek <pavel@suse.cz>
Acked-by: N"Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/aperture_64.c

@@ -18,6 +18,7 @@
 #include <linux/pci.h>
 #include <linux/bitops.h>
 #include <linux/ioport.h>
+#include <linux/suspend.h>
 #include <asm/e820.h>
 #include <asm/io.h>
 #include <asm/gart.h>
@@ -76,6 +77,8 @@ static u32 __init allocate_aperture(void)
 	printk(KERN_INFO "Mapping aperture over %d KB of RAM @ %lx\n",
 			aper_size >> 10, __pa(p));
 	insert_aperture_resource((u32)__pa(p), aper_size);
+	register_nosave_region((u32)__pa(p) >> PAGE_SHIFT,
+				(u32)__pa(p+aper_size) >> PAGE_SHIFT);
 
 	return (u32)__pa(p);
 }