defconfig: Enable remote debugger support for sdm670

Adding remote debugger device configuration. The Remote Debugger driver
allows a debugger running on a host PC to communicate with a remote
stub running on peripheral subsystems.

Change-Id: I032208d579205965286726401decbe3c4edcc1c9
Signed-off-by: Tharun Kumar Merugu <mtharu@codeaurora.org>