Fix test_system_health issue (sonic-net#21216)

1. Only when dut is mellanox, we can call get_platform_data to get platform info
2. Relevant issue: sonic-net#21183

Author: JibinBao

tests/common/fixtures/duthost_utils.py

@@ -551,8 +551,11 @@ def is_support_fan(duthosts, rand_one_dut_hostname):
     Check if dut has fan
     """
     duthost = duthosts[rand_one_dut_hostname]
-    platform_data = get_platform_data(duthost)
-    return platform_data['fans']['number'] > 0
+    if is_mellanox_device(duthost):
+        platform_data = get_platform_data(duthost)
+        return platform_data['fans']['number'] > 0
+    else:
+        return True
 
 
 @pytest.fixture(scope='module')
@@ -561,8 +564,11 @@ def is_support_psu(duthosts, rand_one_dut_hostname):
     Check if dut has psu
     """
     duthost = duthosts[rand_one_dut_hostname]
-    platform_data = get_platform_data(duthost)
-    return platform_data['psus']['number'] > 0
+    if is_mellanox_device(duthost):
+        platform_data = get_platform_data(duthost)
+        return platform_data['psus']['number'] > 0
+    else:
+        return True
 
 
 def separated_dscp_to_tc_map_on_uplink(dut_qos_maps_module):