package/zlib: zlib-ng only available on some archs

Upstream has code only for those architectures, with no fallback
generic code, so we must restrict zlib-ng to only those four archs...

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Nicolas Cavallari <Nicolas.Cavallari@green-communications.fr>
Cc: Adam Duskett <aduskett@gmail.com>
Cc: Stefan Fröberg <stefan.froberg@petroprogram.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[Thomas: fix typoes in the Config.in option name.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/zlib/Config.in

@@ -1,3 +1,10 @@
+config BR2_PACKAGE_ZLIB_NG_ARCH_SUPPORTS
+	bool
+	default y if BR2_arm
+	default y if BR2_aarch64
+	default y if BR2_i386
+	default y if BR2_x86_64
+
 config BR2_PACKAGE_ZLIB
 	bool "zlib support"
 	help
@@ -22,6 +29,7 @@ config BR2_PACKAGE_LIBZLIB
 
 config BR2_PACKAGE_ZLIB_NG
 	bool "zlib-ng"
+	depends on BR2_PACKAGE_ZLIB_NG_ARCH_SUPPORTS
 	select BR2_PACKAGE_HAS_ZLIB
 	help
 	  Zlib replacement with optimizations for