Added fix for issue:21371 update cp and dp states when midplane goes down (#584)

Author: rameshraghupathy

sonic-chassisd/scripts/chassisd

@@ -775,28 +775,22 @@ class SmartSwitchModuleUpdater(ModuleUpdater):
 
     def update_dpu_state(self, key, state):
         """
-        Update DPU state in chassisStateDB using the given key.
+        Update specific DPU state fields in chassisStateDB using the given key.
         """
         try:
             # Connect to the CHASSIS_STATE_DB using daemon_base
             if not self.chassis_state_db:
                 self.chassis_state_db = daemon_base.db_connect("CHASSIS_STATE_DB")
 
-            # Fetch the current data for the given key and convert it to a dict
-            current_data = self._convert_to_dict(self.chassis_state_db.hgetall(key))
-
-            if current_data:
-                self.chassis_state_db.delete(key)
-
-            # Prepare the updated data
+            # Prepare the fields to update
             updates = {
                 "dpu_midplane_link_state": state,
                 "dpu_midplane_link_reason": "",
                 "dpu_midplane_link_time": get_formatted_time(),
             }
-            current_data.update(updates)
 
-            for field, value in current_data.items():
+            # Update each field directly
+            for field, value in updates.items():
                 self.chassis_state_db.hset(key, field, value)
 
         except Exception as e: