CONFIG_ETRAX_SER1_DTR_ON_PB_BIT is not available for thedefaultarchitecture x86.
Result is shown for architecture cris
default or selected kernelversion does not have config value CONFIG_ETRAX_SER1_DTR_ON_PB_BIT.
Result is shown for kernelversion 6.7-rc3

Ser1 DTR on PB bit (-1 = not used)

configname: CONFIG_ETRAX_SER1_DTR_ON_PB_BIT

Linux Kernel Configuration
└─>Ser1 DTR on PB bit (-1 = not used)
In linux kernel since version 2.6.12  
Specify the pin of the PB port to carry the DTR signal for serial
port 1.