cxl/mem: Fix UAPI command comment

cxl/mem: Fix UAPI command comment

The command comment had grammatical errors.  In an attempt to fix those
it was noted that the comment and the query command were not in sync.

Now that the query command returns excluded and device unsupported
command information.  Update the kdoc and fix the grammatical errors.

[1] https://lore.kernel.org/all/63b4ec4e37cc1_5178e2941d@dwillia2-xfh.jf.intel.com.notmuch/

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20221222-cxl-misc-v4-4-62f701c1cdd1@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>