configs: drop redundant IPv6 option

Drop the buildroot toolchain IPv6 option from the only config that's got
it since it's now a non-option.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

configs/armadeus_apf9328_defconfig

@@ -6,7 +6,6 @@ BR2_arm920t=y
 BR2_PACKAGE_GDB=y
 BR2_PACKAGE_HOST_GDB=y
 BR2_ENABLE_LOCALE_PURGE=y
-BR2_TOOLCHAIN_BUILDROOT_INET_IPV6=y
 BR2_TOOLCHAIN_BUILDROOT_INET_RPC=y
 BR2_TOOLCHAIN_BUILDROOT_LOCALE=y
 BR2_TOOLCHAIN_BUILDROOT_CXX=y