The symbols can no longer be used as loadable modules, leading to a harmless Kconfig
warning:

arch/arm/configs/imote2_defconfig:60:warning: symbol value 'm' invalid for NF_CT_PROTO_UDPLITE
arch/arm/configs/imote2_defconfig:59:warning: symbol value 'm' invalid for NF_CT_PROTO_SCTP
arch/arm/configs/ezx_defconfig:68:warning: symbol value 'm' invalid for NF_CT_PROTO_UDPLITE
arch/arm/configs/ezx_defconfig:67:warning: symbol value 'm' invalid for NF_CT_PROTO_SCTP

Let's make them built-in.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>