rockchip: rk3128: remove noop file

arch_cpu_init is already returning 0 in its weak definition in
common/board_f.c so let's just remove the file entirely since nothing
else is done in it.

Cc: Quentin Schulz <foss+uboot@0leil.net>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>

arch/arm/mach-rockchip/rk3128/Makefile

@@ -4,6 +4,5 @@
 # SPDX-License-Identifier:     GPL-2.0+
 #
 
-obj-y += rk3128.o
 obj-y += syscon_rk3128.o
 obj-y += clk_rk3128.o

arch/arm/mach-rockchip/rk3128/rk3128.c

@@ -1,13 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- * Copyright (c) 2017 Rockchip Electronics Co., Ltd
- */
-#include <common.h>
-#include <init.h>
-
-int arch_cpu_init(void)
-{
-	/* We do some SoC one time setting here. */
-
-	return 0;
-}