smb/server: get compression format in get_file_compression_info()

smb/server: get compression format in get_file_compression_info()

I have added `filecompressioninfo` subcommand to `smbinfo`
in cifs-utils.git.

Example:

  1. client: smbinfo setcompression lznt1 /mnt/file
  2. client: smbinfo filecompressioninfo /mnt/file
             Compressed File Size: 104857600
             Compression Format: 2 (LZNT1)
             Compression Unit Shift: 0
             Chunk Shift: 0
             Cluster Shift: 0

Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>