[Mellanox] Remove reset_from_comex from reboot cause mapping (#15793) (#16039)

Author: mssonicbld

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

@@ -731,7 +731,6 @@ def initialize_reboot_cause(self):
             'reset_hotswap_or_halt'     :   self.REBOOT_CAUSE_HARDWARE_OTHER,
             'reset_voltmon_upgrade_fail':   self.REBOOT_CAUSE_HARDWARE_OTHER,
             'reset_reload_bios'         :   self.REBOOT_CAUSE_HARDWARE_BIOS,
-            'reset_from_comex'          :   self.REBOOT_CAUSE_HARDWARE_CPU,
             'reset_fw_reset'            :   self.REBOOT_CAUSE_HARDWARE_RESET_FROM_ASIC,
             'reset_from_asic'           :   self.REBOOT_CAUSE_HARDWARE_RESET_FROM_ASIC,
             'reset_long_pb'             :   self.REBOOT_CAUSE_HARDWARE_BUTTON,