Add ability to dipslay SMB3 share flags and capabilities for debugging

SMB3 protocol adds various optional per-share capabilities (and
SMB3.02 adds one more beyond that).  Add ability to dump
(/proc/fs/cifs/DebugData) the share capabilities and share flags to
improve debugging.

Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>