default or selected kernelversion does not have config value CONFIG_DVB_CINERGYT2_STREAM_BUF_SIZE.
Result is shown for kernelversion 5.3.7

Size of URB Stream Buffers for Highspeed Transfers

configname: CONFIG_DVB_CINERGYT2_STREAM_BUF_SIZE

Linux Kernel Configuration
└─>Device Drivers
└─>Multimedia devices
└─>DVB/ATSC adapters
└─>Size of URB Stream Buffers for Highspeed Transfers
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
Should be a multiple of native buffer size of 512 bytes.
Default value is a safe choice.

You may increase this number if you are using this device in a
Server Environment with many high-traffic USB Highspeed devices
sharing the same USB bus.