[Nvidia-BF] Enable CHASSIS_DB on DPU (sonic-net#20534)

- Why I did it
To enable CHASSIS_DB support on DPU, This is required to communicate health/ operation status information to the switch from the DPU

- How I did it
By adding chassisdb.conf file in the platform folder, This creates a link to the DB hosted on the Smartswitch platform

- How to verify it
Execute the following command on DPU:
sonic-db-cli CHASSIS_STATE_DB HSET DPU_TABLE_1 KEY_1 VALUE_1" sonic-db-cli DPU_APPL_DB HGETALL DPU_TABLE_1
and check if the data is available in the Switch
docker exec -it database-chassis bash -c "sonic-db-cli CHASSIS_STATE_DB HGETALL DPU_TABLE_1"

Author: gpunathilell

device/nvidia-bluefield/arm64-nvda_bf-bf3comdpu/chassisdb.conf

@@ -0,0 +1 @@
+chassis_db_address=169.254.200.254