x86, pat: Fix memory leak in free_memtype

Reserve_memtype will allocate memory for new memtype, but
in free_memtype, after the memtype erased from rbtree, the
memory is not freed.

Changes since V1:
	make rbt_memtype_erase return erased memtype so that
	it can be freed in free_memtype.

[ hpa: not for -stable: 2.6.34 and earlier not affected ]

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
LKML-Reference: <1274838670-8731-1-git-send-email-dfeng@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Jack Steiner <steiner@sgi.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/mm/pat_rbtree.c

@@ -231,16 +231,17 @@ int rbt_memtype_check_insert(struct memtype *new, unsigned long *ret_type)
 	return err;
 }
 
-int rbt_memtype_erase(u64 start, u64 end)
+struct memtype *rbt_memtype_erase(u64 start, u64 end)
 {
 	struct memtype *data;
 
 	data = memtype_rb_exact_match(&memtype_rbroot, start, end);
 	if (!data)
-		return -EINVAL;
+		goto out;
 
 	rb_erase(&data->rb, &memtype_rbroot);
-	return 0;
+out:
+	return data;
 }
 
 struct memtype *rbt_memtype_lookup(u64 addr)