add dependency on ipcalc
    
    ipcalc is needed for generating 45route-static.conf. However,
    on newer Fedora, e.g. 34, dracut-network drops dependency on
    dhcp-client which requires ipcalc. Make kexec-tools explicitly
    depends on ipcalc.
    
    Reported-by: Jie Li <jieli@redhat.com>
    Signed-off-by: Coiby Xu <coxu@redhat.com>
    Acked-by: Kairui Song <kasong@redhat.com>