Handle un-readable kfd properties files

Some systems have kfd sysfs properties entries that
are unreadable--for example, when a multi-gpu system is
dividing the gpus among containers, each container may
only be able to access certain gpus.

Previously, all kfd topology node properties entries were
assumed to be valid. Now, we check for readability before
declaring them "valid".

Fixes SWDEV-240169

Also:
* remove an assertion that would happen when no pcie
device identifier files are found on the system.
* fix cpplint issues

Change-Id: I74321b685159dd2628c890b33c39ad82988cb9dd

include/rocm_smi/rocm_smi.h

@@ -1799,8 +1799,9 @@ rsmi_status_t rsmi_dev_temp_metric_get(uint32_t dv_ind, uint32_t sensor_type,
  *  @retval ::RSMI_STATUS_INVALID_ARGS the provided arguments are not valid
  *
  */
-rsmi_status_t rsmi_dev_volt_metric_get(uint32_t dv_ind, rsmi_voltage_type_t sensor_type,
-                      rsmi_voltage_metric_t metric, int64_t *voltage);
+rsmi_status_t rsmi_dev_volt_metric_get(uint32_t dv_ind,
+                               rsmi_voltage_type_t sensor_type,
+                              rsmi_voltage_metric_t metric, int64_t *voltage);
 /** @} */  // end of PhysQuer
 
 /*****************************************************************************/