Revert "package/libpng: fix arm soft-float build"

This reverts commit 4875dbed58837174780e3f7c6ec7ef419fdbe9fe.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libpng/libpng.mk

@@ -17,9 +17,7 @@ HOST_LIBPNG_DEPENDENCIES = host-pkgconf host-zlib
 LIBPNG_CONFIG_SCRIPTS = libpng$(LIBPNG_SERIES)-config libpng-config
 LIBPNG_CONF_OPTS = --disable-tools
 
-ifeq ($(BR2_aarch64),y)
-LIBPNG_CONF_OPTS += --enable-arm-neon
-else ifeq ($(BR2_ARM_CPU_HAS_NEON):$(BR2_ARM_SOFT_FLOAT),y:)
+ifeq ($(BR2_ARM_CPU_HAS_NEON)$(BR2_aarch64),y)
 LIBPNG_CONF_OPTS += --enable-arm-neon
 else
 LIBPNG_CONF_OPTS += --disable-arm-neon