LU-17501 libcfs: adding X for cpu pattern

LU-17501 libcfs: adding X for cpu pattern

Added 'X' pattern to cpu_pattern such that "X[1]" will remove cpu 1
regardless of what partition it is in.

Using "N X" will set the default NUMA node layout before excluding.
Using "X" without 'N' will set the layout based on npartitions.

This is similarily true for 'C', use 'N' for NUMA layout and not for
an npartitions based layout.

Signed-off-by: Frederick Dilger <fdilger@whamcloud.com>
Change-Id: I6276f78ecab401ed106b75ab798e5f805ef19f93
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56617
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>