[SFP-Refactor] Modify transceiver dict vendor key name

[aravindmani-1]

With earlier SFP refactor, 'hardware_rev' is used in place of 'vendor_rev'.
With new SFP refactor, this issue is fixed. In some platforms, vendor_rev key is not defined in transceiver dictionary.
'hardware_rev' is not mentioned in SFF specs except CMIS.
If sonic-net/sonic-platform-daemons#231 is integrated, xcvrd will crash for the vendors as 'vendor_rev' key is not defined.
All the repository has to change 'hardware_rev' key to 'vendor_rev' key as it'd mislead the EEPROM information.