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>
diff --git a/arch/arm/cpu/armv7/zynq/Makefile b/arch/arm/cpu/armv7/zynq/Makefile
index 901f2ce..bf29b4d 100644
--- a/arch/arm/cpu/armv7/zynq/Makefile
+++ b/arch/arm/cpu/armv7/zynq/Makefile
@@ -14,4 +14,5 @@
 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