x86, UV: system table in bios accessed after unmap

Use the copy of UV system table in kernel memory, not the one in
bios after unmapping.
Signed-off-by: Russ Anderson <rja@sgi.com>
LKML-Reference: <20090330225240.GA22776@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/bios_uv.c

@@ -182,7 +182,8 @@ void uv_bios_init(void)
 	memcpy(&uv_systab, tab, sizeof(struct uv_systab));
 	iounmap(tab);
 
-	printk(KERN_INFO "EFI UV System Table Revision %d\n", tab->revision);
+	printk(KERN_INFO "EFI UV System Table Revision %d\n",
+					uv_systab.revision);
 }
 #else	/* !CONFIG_EFI */