x86_64: remove debug code from arch_add_memory()

[Gary Hade <garyhade@us.ibm.com>]

Gets rid of dmesg spam created during physical memory hot-add which
will very likely confuse users.  The change removes what appears to
be debugging code which I assume was unintentionally included in:
  x86: arch/x86/mm/init_64.c printk fixes
  commit 10f22dde556d1ed41d55355d1fb8ad495f9810c8

Signed-off-by: Gary Hade <garyhade@us.ibm.com>

---
 arch/x86/mm/init_64.c |    1 -
 1 file changed, 1 deletion(-)

Index: linux-2.6.28-rc2/arch/x86/mm/init_64.c
===================================================================
--- linux-2.6.28-rc2.orig/arch/x86/mm/init_64.c	2008-10-28 15:39:05.000000000 -0700
+++ linux-2.6.28-rc2/arch/x86/mm/init_64.c	2008-10-28 15:39:32.000000000 -0700
@@ -836,7 +836,6 @@
 		max_pfn_mapped = last_mapped_pfn;
 
 	ret = __add_pages(zone, start_pfn, nr_pages);
-	WARN_ON(1);
 
 	return ret;
 }