Add support for new Compression Negotiate Context

[Steve French]

Add support to negotiate the compression context, and also saved off
to display in /proc/fs/cifs/DebugData.  Future patch will add use for
it on the wire.

Note in /proc/fs/cifs/DebugData below (mounted to Windows 10) it defaulted
to LZ77 compression algorithm.  See MS-SMB2 2.2.3.1 and and MS-XCA

Servers:
Number of credits: 326 Dialect 0x311 COMPRESS_LZ77 signed
1) Name: 192.168.92.17 Uses: 1 Capability: 0x300067    Session Status:
1 TCP status: 1 Instance: 1


-- 
Thanks,

Steve
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