update default crashkernel value
    
    Resolves: bz1895258
    Upstream: Fedora
    Conflict: None
    
    commit 34d27c4c308d9eddc35ff2c81bfe3b1cef5749a5
    Author: Coiby Xu <coxu@redhat.com>
    Date:   Tue Nov 16 09:12:49 2021 +0800
    
        update default crashkernel value
    
        It has been decided to increase default crashkernel value to reduce the
        possibility of OOM.
    
        Fixes: 7b7ddab ("kdump-lib.sh: kdump_get_arch_recommend_size uses crashkernel.default")
    
        Reviewed-by: Pingfan Liu <piliu@redhat.com>
        Reviewed-by: Philipp Rudo <prudo@redhat.com>
        Signed-off-by: Coiby Xu <coxu@redhat.com>
    
    Signed-off-by: Coiby Xu <coxu@redhat.com>