defconfig: msm8960: Enable the RTB tracer

Enable default support for the register trace buffer (RTB) tracer.
This logs all reads and writes from memory mapped I/O into an
uncached region of memory for use in debugging resets. This also
turns on additional code to get a more accurate ETB dump.

Change-Id: Ifbb9fa570bd395cdc17dbeac98559522e3b69de0
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>