[PMON] [Mellanox] fix syseepromd issue on simx (sonic-net#8131)

Avoid initializing sfp/thermal/components/fan/psu/leds on simx and create vpd_info file on hw_management when we use mellanox simulator platform

- Why I did it
this is a fix for issue in mellanox simulator platforms. the syseepromd failed on the pmon docker. also "decode-syseeprom" failed also

- How I did it
before initializing thermal/components/fan/psu/leds --> check if we are running on simx
creating the vpd_info on the hw_management folder.

- How to verify it
check if syseepromd process was loaded properly on the pmon docker.
decode-syseeprom is working well without errors/warnings

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

@@ -7,9 +7,10 @@
 #############################################################################
 import os
 import time
+import subprocess
 
 from sonic_py_common.logger import Logger
-
+from sonic_py_common.device_info import get_platform, get_path_to_platform_dir
 try:
     from sonic_platform_base.sonic_eeprom import eeprom_tlvinfo
 except ImportError as e:
@@ -25,6 +26,16 @@
 #
 EEPROM_SYMLINK = "/var/run/hw-management/eeprom/vpd_info"
 
+platform_name = get_platform()
+if 'simx' in platform_name:
+    platform_path = get_path_to_platform_dir()
+
+    if not os.path.exists(EEPROM_SYMLINK):
+        if not os.path.exists(os.path.dirname(EEPROM_SYMLINK)):
+            os.makedirs(os.path.dirname(EEPROM_SYMLINK))
+
+        subprocess.check_call(['/usr/bin/xxd', '-r', '-p', 'syseeprom.hex', EEPROM_SYMLINK], cwd=platform_path)
+
 class Eeprom(eeprom_tlvinfo.TlvInfoDecoder):
     RETRIES = 3
 

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

@@ -7,6 +7,7 @@
 try:
     from sonic_platform_base.platform_base import PlatformBase
     from sonic_platform.chassis import Chassis
+    from sonic_py_common.device_info import get_platform
     from . import utils
 except ImportError as e:
     raise ImportError(str(e) + "- required module not found")
@@ -15,11 +16,13 @@ class Platform(PlatformBase):
     def __init__(self):
         PlatformBase.__init__(self)
         self._chassis = Chassis()
-        self._chassis.initialize_psu()
         self._chassis.initialize_eeprom()
-        if utils.is_host():
-            self._chassis.initialize_components()
-            self._chassis.initizalize_system_led()
-        else:
-            self._chassis.initialize_fan()
-            self._chassis.initialize_thermals()
+        platform_name = get_platform()
+        if "simx" not in platform_name:
+            self._chassis.initialize_psu()
+            if utils.is_host():
+                self._chassis.initialize_components()
+                self._chassis.initizalize_system_led()
+            else:
+                self._chassis.initialize_fan()
+                self._chassis.initialize_thermals()