netfilter: xtables: disable 32bit compat interface by default

This defaulted to 'y' because before this knob existed the 32bit
compat layer was always compiled in if CONFIG_COMPAT was set.

32bit iptables on 64bit kernel isn't common anymore, so remove
the default-y now.
Signed-off-by: Florian Westphal <fw@strlen.de>

net/netfilter/Kconfig

@@ -753,7 +753,6 @@ if NETFILTER_XTABLES
 config NETFILTER_XTABLES_COMPAT
 	bool "Netfilter Xtables 32bit support"
 	depends on COMPAT
-	default y
 	help
 	   This option provides a translation layer to run 32bit arp,ip(6),ebtables
 	   binaries on 64bit kernels.