fadump: improve fadump-howto.txt about remote dump target setup
    
    upstream: fedora
    related:  bz2003832
    conflict: none
    
    commit da6f381b081469fccf12110a398d03d1c0810b3f
    Author: Hari Bathini <hbathini@linux.ibm.com>
    Date:   Thu Feb 18 14:12:00 2021 +0530
    
        fadump: improve fadump-howto.txt about remote dump target setup
    
        While fadump-howto.txt talks about what happens to network interface
        name on setting up a remote dump target in FADump mode, it doesn't
        explicitly specify the negative consequences of it. Make it explicit
        and provide a recommendation to overcome the same.
    
        Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
        Acked-by: Kairui Song <kasong@redhat.com>
    
    Signed-off-by: Tao Liu <ltao@redhat.com>