cbmem_top: Fix comment and remove upper limit

There's no such limit on 64 Bit coreboot builds.

* Fix comment in cbmem.h
* Remove 4 GiB limit on Cavium SoCs

Tested on opencellular/elgon.
Still boots Linux as payload.

Change-Id: I8c9c6a5ff81bee48311e8bf8e383d1a032ea3a6d
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/30609
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/src/soc/cavium/cn81xx/cbmem.c b/src/soc/cavium/cn81xx/cbmem.c
index 397fd26..bb6fa18 100644
--- a/src/soc/cavium/cn81xx/cbmem.c
+++ b/src/soc/cavium/cn81xx/cbmem.c
@@ -2,6 +2,7 @@
  * This file is part of the coreboot project.
  *
  * Copyright 2014 Rockchip Inc.
+ * Copyright 2019 9Elements GmbH <patrick.rudolph@9elements.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -22,6 +23,5 @@
 void *cbmem_top(void)
 {
 	/* Make sure not to overlap with reserved ATF scratchpad */
-	return (void *)min((uintptr_t)_dram + (sdram_size_mb() - 1) * MiB,
-			   4ULL * GiB);
+	return (void *)((uintptr_t)_dram + (sdram_size_mb() - 1) * MiB);
 }