cxl/pci: Hold memdev lock in cxl_event_trace_record()

cxl/pci: Hold memdev lock in cxl_event_trace_record()

cxl_event_config() invokes cxl_mem_get_event_record() to get remain
event logs from CXL device during cxl_pci_probe(). If CXL memdev probing
failed before that, it is possible to access an invalid endpoint. So
adding a cxlmd->driver binding status checking inside
cxl_dpa_to_region() to ensure the corresponding endpoint is valid.

Besides, cxl_event_trace_record() needs to hold memdev lock to invoke
cxl_dpa_to_region() to ensure the memdev probing completed. It is
possible that cxl_event_trace_record() is invoked during the CXL memdev
probing, especially user or cxl_acpi triggers CXL memdev re-probing.

Suggested-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Li Ming <ming.li@zohomail.com>
Link: https://patch.msgid.link/20260314-fix_access_endpoint_without_drv_check-v2-3-4c09edf2e1db@zohomail.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>