Hi Amit,
It just means that those 2 channels only operate as 3.3V LVTTL mode. If your drives accept LVTTL signals they can be used. Actually the specifications for 5V TTL and 3.3V LVTTL are the same (High level must be 2.4V). If your drives require 4.5V you can add an external driver. Such as:
https://cnc4pc.com/differential-line-driver.html
HTH
Regards