PCI/AER: Use guard() in cxl_rch_handle_error_iter()

PCI/AER: Use guard() in cxl_rch_handle_error_iter()

cxl_rch_handle_error_iter() includes a call to device_lock() using a goto
for multiple return paths. Improve readability and maintainability by
using the guard() lock variant.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20260114182055.46029-13-terry.bowman@amd.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>