cxl: Store QTG IDs and related info to the CXL memory device context

cxl: Store QTG IDs and related info to the CXL memory device context

Once the QTG ID _DSM is executed successfully, the QTG ID is retrieved from
the return package. Create a list of entries in the cxl_memdev context and
store the QTG ID as qos_class token and the associated DPA range. This
information can be exposed to user space via sysfs in order to help region
setup for hot-plugged CXL memory devices.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/170319625109.2212653.11872111896220384056.stgit@djiang5-mobl3
Signed-off-by: Dan Williams <dan.j.williams@intel.com>