Dear Krishna,
As per the provided details, you are going for the patch upgrade on the SP12 version for SAP MDM 7.1.
For any patch upgrade, it does not require deep level of testing as the application features and functionality is going to remain same.
Patch upgrade would only be relevant for fixing the specific bugs by upgrading from lower patch to higher patch.
I would recommend to perform basic test centered towards the Bug which is going to be eliminated with the Patch upgrade and rest depends on the Business Side to decide if they want to perform any specific testing.
Regards,
Gaurav