kmod-nft-reject: Fix for "nft_reject_ipv4.ko missing" warning

kmod-nft-reject: Fix for "nft_reject_ipv4.ko missing" warning

Seeing the following:

    ERROR: module '/home/philipp/lede/build_dir/target-x86_64_musl/linux-x86_64/linux-5.4.33/net/ipv4/netfilter/nft_reject_ipv4.ko' is missing.
    modules/netfilter.mk:1068: recipe for target '/home/philipp/lede/bin/targets/x86/64/packages/kmod-nft-core_5.4.33-1_x86_64.ipk' failed
    make[3]: *** [/home/philipp/lede/bin/targets/x86/64/packages/kmod-nft-core_5.4.33-1_x86_64.ipk] Error 1

Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>