Hello student!

Yes you can do MTech in mechatronics after BTech in computer engineering.
Mechatronics engineering consists subjects of :

• Mechanics
• Electronics
• Computer Engineering
• Systems Engineering
• Telecommunications Engineering
• Control Engineering.

You must get 60% above in your BTech (equivalent CGPA).
Also, you must attempt your GATE paper for Mechatronics.
List of colleges providing mechatronics engineering stream:
https://engineering.careers360.com/colleges/list-of-mechatronics-engineering-colleges-in-india

Hope this helps :)
Best of luck!