[Mellanox] Update Mellanox-SN5600-C256S1, Mellanox-SN5600-C224O8 buffers and DSCP mapping (#562)

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#### Why I did it
To update buffers for Mellanox-SN5600-C256S1 and Mellanox-SN5600-C224O8
##### Work item tracking
- Microsoft ADO **(number only)**:

#### How I did it
Update proper files - qos.json.j2, buffer_defaults_objects.j2, buffers_defaults_t0/t1.j2
#### How to verify it
Run test and check SDK dumps values
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Author: mssonicbld

device/mellanox/x86_64-nvidia_sn5600-r0/Mellanox-SN5600-C224O8/buffers_defaults_objects.j2

@@ -0,0 +1 @@
+../Mellanox-SN5600-C256S1/buffers_defaults_objects.j2

device/mellanox/x86_64-nvidia_sn5600-r0/Mellanox-SN5600-C224O8/buffers_defaults_objects.j2

@@ -1,6 +1,6 @@
 {#
     SPDX-FileCopyrightText: NVIDIA CORPORATION & AFFILIATES
-    Copyright (c) 2024 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+    Copyright (c) 2024-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
     Apache-2.0
 
     Licensed under the Apache License, Version 2.0 (the "License");
@@ -15,11 +15,17 @@
     See the License for the specific language governing permissions and
     limitations under the License.
 #}
-{% set default_cable = '40m' %}
-{% set ingress_lossless_pool_size =  '144188416' %}
-{% set ingress_lossless_pool_xoff =  '1024' %}
+{% set default_cable = '0m' %}
+{%-set ports2cable = {
+            'torrouter_server'       : '0m',
+            'leafrouter_torrouter'   : '0m',
+            'spinerouter_leafrouter' : '0m'
+       }
+-%}
+{% set ingress_lossless_pool_size =  '144189440' %}
+{% set ingress_lossless_pool_xoff =  '0' %}
 {% set egress_lossless_pool_size =  '158229504' %}
-{% set egress_lossy_pool_size =  '144188416' %}
+{% set egress_lossy_pool_size =  '144189440' %}
 
 {% import 'buffers_defaults_objects.j2' as defs with context %}
 

device/mellanox/x86_64-nvidia_sn5600-r0/Mellanox-SN5600-C224O8/buffers_defaults_t0.j2

@@ -1,6 +1,6 @@
 {#
     SPDX-FileCopyrightText: NVIDIA CORPORATION & AFFILIATES
-    Copyright (c) 2024 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+    Copyright (c) 2024-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
     Apache-2.0
 
     Licensed under the Apache License, Version 2.0 (the "License");
@@ -15,18 +15,17 @@
     See the License for the specific language governing permissions and
     limitations under the License.
 #}
-{% set default_cable = '250m' %}
-{% set ingress_lossless_pool_size =  '144188416' %}
-{% set ingress_lossless_pool_xoff =  '1024' %}
-{% set egress_lossless_pool_size =  '158229504' %}
-{% set egress_lossy_pool_size =  '144188416' %}
-
+{% set default_cable = '0m' %}
 {%-set ports2cable = {
-            'torrouter_server'       : '40m',
-            'leafrouter_torrouter'   : '250m',
-            'spinerouter_leafrouter' : '1000m'
+            'torrouter_server'       : '0m',
+            'leafrouter_torrouter'   : '0m',
+            'spinerouter_leafrouter' : '0m'
        }
 -%}
+{% set ingress_lossless_pool_size =  '144189440' %}
+{% set ingress_lossless_pool_xoff =  '0' %}
+{% set egress_lossless_pool_size =  '158229504' %}
+{% set egress_lossy_pool_size =  '144189440' %}
 
 {% import 'buffers_defaults_objects.j2' as defs with context %}
 

device/mellanox/x86_64-nvidia_sn5600-r0/Mellanox-SN5600-C224O8/buffers_defaults_t1.j2

@@ -1 +1 @@
-../../x86_64-mlnx_msn2700-r0/ACS-MSN2700/qos.json.j2
+../Mellanox-SN5600-C256S1/qos.json.j2