fadump-init: clean up mount points properly
    
    Resolves: bz1924115
    Conflict: None
    Upstream: Fedora
    
    commit 97930d3ccad5ce090d3160a5781549b081467655
    Author: Kairui Song <kasong@redhat.com>
    Date:   Mon Jun 28 13:57:27 2021 +0800
    
        fadump-init: clean up mount points properly
    
        When running with squash module enabled for both initramfs, /dev and
        /run are also mounted by squash-init, so move them to newroot as well,
        else they might leak.
    
        Also pass `-d` to umount so loop devices (if used) will be force freed.
    
        Signed-off-by: Kairui Song <kasong@redhat.com>
        Acked-by: Hari Bathini <hbathini@linux.ibm.com>
    
    Signed-off-by: Kairui Song <kasong@redhat.com>