x86, pat: Proper init of memtype subtree_max_end

subtree_max_end that was recently added to struct memtype was not getting
properly initialized resulting in

WARNING: kmemcheck: Caught 64-bit read from uninitialized memory
in memtype_rb_augment_cb()
reported here
https://bugzilla.kernel.org/show_bug.cgi?id=16092

This change fixes the problem.

Reported-by: Christian Casteyde <casteyde.christian@free.fr>
Tested-by: Christian Casteyde <casteyde.christian@free.fr>
Signed-off-by: Venkatesh Pallipadi <venki@google.com>
LKML-Reference: <1276217101-11515-1-git-send-email-venki@google.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
index f537087..f20eeec 100644
--- a/arch/x86/mm/pat_rbtree.c
+++ b/arch/x86/mm/pat_rbtree.c
@@ -226,6 +226,7 @@
 		if (ret_type)
 			new->type = *ret_type;
 
+		new->subtree_max_end = new->end;
 		memtype_rb_insert(&memtype_rbroot, new);
 	}
 	return err;