x86: remove end_pfn in 64bit

and use max_pfn directly.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/srat_64.c b/arch/x86/mm/srat_64.c
index b67f5a1..0fd67b8 100644
--- a/arch/x86/mm/srat_64.c
+++ b/arch/x86/mm/srat_64.c
@@ -299,7 +299,7 @@
 			pxmram = 0;
 	}
 
-	e820ram = end_pfn - absent_pages_in_range(0, end_pfn);
+	e820ram = max_pfn - absent_pages_in_range(0, max_pfn);
 	/* We seem to lose 3 pages somewhere. Allow a bit of slack. */
 	if ((long)(e820ram - pxmram) >= 1*1024*1024) {
 		printk(KERN_ERR