Bluetooth: tests: shell: br : increase rfcomm dlc stack size

[makeshi]

For the shell RFCOMM case, these is a stack overflow problem when do disconnect, so need to increase the CONFIG_BT_RFCOMM_DLC_STACK_SIZE. After testing, the stack here requires at least 388 bytes. With an additional 10% buffer, so set this size to 420.

[jhedberg]

How tight on memory are you with the platforms that you're targeting for? Generally, it's better to avoid special-casing applications and having conditional defaults, if a single default value can cover most cases. Maybe consider removing the conditional default for HFP in subsys/bluetooth/classic/Kconfig and just have a single default of 512? (again, I don't know the memory situation for your platforms, so please correct me if you think this is a bad idea)

[makeshi]

@jhedberg My platform is based on NXP's EVK1170, which uses an ARM Cortex-M7 core.
With a default single-core configuration of 512 meet my requirements. And @lylezhu2012 How about this proposal using single default of 512 by removing the conditional default for HFP ?

[lylezhu2012]

And @lylezhu2012 How about this proposal using single default of 512 by removing the conditional default for HFP ?

Yes. I think we can do it.

[makeshi]

And @lylezhu2012 How about this proposal using single default of 512 by removing the conditional default for HFP ?

Yes. I think we can do it.

OK, I will update the PR with the proposal