[Mellanox] Fix issue: read data from eeprom should trim tail \0 (#5670)

Now we are reading base mac, product name from eeprom data, and the data read from eeprom contains multiple "\0" characters at the end, need trim them to make the string clean and display correct.

platform/mellanox/mlnx-platform-api/sonic_platform/eeprom.py

@@ -82,18 +82,26 @@ def _load_eeprom(self):
         self._base_mac = self.mgmtaddrstr(eeprom)
         if self._base_mac is None:
             self._base_mac = "Undefined."
+        else:
+            self._base_mac = self._base_mac.strip('\0')
 
         self._serial_str = self.serial_number_str(eeprom)
         if self._serial_str is None:
             self._serial_str = "Undefined."
+        else:
+            self._serial_str = self._serial_str.strip('\0')
 
         self._product_name = self.modelstr(eeprom)
         if self._product_name is None:
             self._product_name = "Undefined."
+        else:
+            self._product_name = self._product_name.strip('\0')
 
         self._part_number = self.part_number_str(eeprom)
         if self._part_number is None:
             self._part_number = "Undefined."
+        else:
+            self._part_number = self._part_number.strip('\0')
 
         original_stdout = sys.stdout
         sys.stdout = StringIO()