With kernel 5.7 in each boot you find the "errror" message: m88ds3103 5-006a: dt addr is 0x21
I think your use of dvb_err is unintentional and perhaps you should lower the severity a bit: _dev_err(&client->dev, "dt addr is 0x%02x", dev->dtaddr); [drivers/media/dvb-frontends/m88ds3103.c line 1904].
With kernel 5.7 in each boot you find the "errror" message: m88ds3103 5-006a: dt addr is 0x21
I think your use of dvb_err is unintentional and perhaps you should lower the severity a bit: _dev_err(&client->dev, "dt addr is 0x%02x", dev->dtaddr); [drivers/media/dvb-frontends/m88ds3103.c line 1904].
In addition your fix still works like a charm!