[libpng16] Added ".align 2" to arm/filter_neon.S to support old GAS assemblers

that don't do alignment correctly.
diff --git a/arm/arm_init.c b/arm/arm_init.c
index b0e929b..9a23e10 100644
--- a/arm/arm_init.c
+++ b/arm/arm_init.c
@@ -130,4 +130,4 @@
    }
 }
 #endif /* PNG_ARM_NEON_OPT > 0 */
-#endif /* PNG_READ_SUPPORTED */
+#endif /* READ */