OvmfPkg/IoMmuDxe: IoMmuFreeBuffer(): clean up DEBUG message
    
    Log all relevant IN parameters on entry. (There are only IN parameters.)
    Beautify the format string.
    
    Cc: Brijesh Singh <brijesh.singh@amd.com>
    Cc: Jordan Justen <jordan.l.justen@intel.com>
    Contributed-under: TianoCore Contribution Agreement 1.1
    Signed-off-by: Laszlo Ersek <lersek@redhat.com>
    Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
    Tested-by: Brijesh Singh <brijesh.singh@amd.com>