ARM: configs: aspeed: Disable IPV6 SIT device

No one is using this device on OpenBMC systems, and there is no code to
manage it in phosphor-networkd (the default OpenBMC userspace) as of
March 2021:

> [...] if you don't add IPv6 addresses to the sit interface
> it doesn't do anything. The defacto way to do that on an interface in
> OpenBMC is to have it managed by phosphor-networkd. On top of this, to
> support sit you would need a way to configure the local / remote IPv4
> addresses used to back it.
Signed-off-by: NJoel Stanley <joel@jms.id.au>

arch/arm/configs/aspeed_g4_defconfig

@@ -48,6 +48,7 @@ CONFIG_INET=y
 CONFIG_IP_MULTICAST=y
 CONFIG_SYN_COOKIES=y
 # CONFIG_INET_DIAG is not set
+# CONFIG_IPV6_SIT is not set
 CONFIG_NETFILTER=y
 # CONFIG_NETFILTER_ADVANCED is not set
 CONFIG_VLAN_8021Q=y

arch/arm/configs/aspeed_g5_defconfig

@@ -60,6 +60,7 @@ CONFIG_SYN_COOKIES=y
 CONFIG_IPV6_ROUTER_PREF=y
 CONFIG_IPV6_ROUTE_INFO=y
 CONFIG_IPV6_OPTIMISTIC_DAD=y
+# CONFIG_IPV6_SIT is not set
 CONFIG_IPV6_MULTIPLE_TABLES=y
 CONFIG_NETFILTER=y
 # CONFIG_NETFILTER_ADVANCED is not set