cxl/core: use sysfs_emit() for attr's _show()

sprintf() is deprecated for sysfs, use preferred sysfs_emit() instead.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Link: https://lore.kernel.org/r/20240112062709.2490947-1-ruansy.fnst@fujitsu.com


Signed-off-by: Dan Williams <dan.j.williams@intel.com>