ARM: zynq: pass "-mfpu=neon" only to lowlevel_init.S

The comment line in arch/arm/cpu/armv7/zynq/config.mk says that
the option "-mfpu=neon" is necessary for compiling lowlevel_init.S.
We do not have to give it to all the source files.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/cpu/armv7/zynq/Makefile

@@ -14,4 +14,5 @@ obj-y	+= ddrc.o
 obj-y	+= slcr.o
 obj-y	+= clk.o
 obj-y	+= lowlevel_init.o
+AFLAGS_lowlevel_init.o := -mfpu=neon
 obj-$(CONFIG_SPL_BUILD)	+= spl.o

arch/arm/cpu/armv7/zynq/config.mk

@@ -1,7 +0,0 @@
-#
-# Copyright (C) 2013 - 2015 Xilinx, Inc. All rights reserved.
-#
-# SPDX-License-Identifier:      GPL-2.0
-#
-# Allow NEON instructions (needed for lowlevel_init.S with GNU toolchain)
-PLATFORM_RELFLAGS += -mfpu=neon