rd.route should use the name from kdump_setup_ifname
    
    This fix bz1854037 which happens because kexec-tools generates rd.route for
    eth0 instead of for kdump-eth0,
     1. "rd.route=168.63.129.16:10.0.0.1:eth0 rd.route=169.254.169.254:10.0.0.1:eth0" is passed to the dracut cmdline by kexec-tools
     2. In the 2rd kernel,
        - dracut/modules.d/40network/net-lib.sh will write /tmp/net.route.eth0 based on rd.route
        - dracut/modules.d/45ifcfg/write-ifcfg.sh will copy /tmp/net.route.eth0 to /tmp/icfg and then copytree /tmp/ifcfg to /run/initramfs/state/etc/sysconfig/network-scripts
     3. NetworkManager will try to get an IP for eth0 regardless of the fact it's a slave NIC and time out
        ```
        $ ip link show
        2: kdump-eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
           link/ether 00:0d:3a:11:86:8b brd ff:ff:ff:ff:ff:ff
        3: eth0: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc mq master kdump-eth0 state UP mode DEFAULT group default qlen 1000
        ```
    
    Reported-by: Huijing Hei <hhei@redhat.com>
    Signed-off-by: Coiby Xu <coxu@redhat.com>
    Acked-by: Kairui Song