Qualcomm ATH13.0CS needs the dependency on kmod-nf-conntrack to pass the build
of kmod-ipt-ipopt. Introduce a conditional dependency on kmod-nf-conntrack
for ipt-ipopt to ensure that the module is only included when
PACKAGE_kmod-nf-conntrack is enabled, preserving the default behavior.
Signed-off-by: Marvin Lu <marvin.lu@wnc.com.tw>