Add to check pcie configuration revision to get the right configurati…

…on. (sonic-net#195)

Platform vendor can add their own logic to determine the pcie
conifiguration revision.

sonic_platform_base/sonic_pcie/pcie_common.py

@@ -19,10 +19,12 @@ class PcieUtil(PcieBase):
     # got the config file path
     def __init__(self, path):
         self.config_path = path
+        self._conf_rev = None
 
     # load the config file
     def load_config_file(self):
-        config_file = self.config_path + "/" + "pcie.yaml"
+        conf_rev = "_{}".format(self._conf_rev) if self._conf_rev else ""
+        config_file = "{}/pcie{}.yaml".format(self.config_path, conf_rev)
         try:
             with open(config_file) as conf_file:
                 self.confInfo = yaml.load(conf_file)
@@ -137,6 +139,8 @@ def get_pcie_aer_stats(self, domain=0, bus=0, device=0, func=0):
     # generate the config file with current pci device
     def dump_conf_yaml(self):
         curInfo = self.get_pcie_device()
-        with open(self.config_path + "/" + "pcie.yaml", "w") as conf_file:
+        conf_rev = "_{}".format(self._conf_rev) if self._conf_rev else ""
+        config_file = "{}/pcie{}.yaml".format(self.config_path, conf_rev)
+        with open(config_file, "w") as conf_file:
             yaml.dump(curInfo, conf_file, default_flow_style=False)
         return