msm: add support for remote debugger driver

The Remote Debugger Driver allows a debugger running on host PC to
communicate with a remote stub running on peripheral subsystems by
implementing a shared memory based transport mechanism. Add support
for the driver.

Change-Id: I0c8a498682d224ee5d5a275c228a75939675095b
Acked-by: Vivek Iyer <viyer@qti.qualcomm.com>
Acked-by: Mahesh Rohera <mrohera@qti.qualcomm.com>
Acked-by: Jay Jayanna <jjayanna@qti.qualcomm.com>
Signed-off-by: Aparna Das <adas@codeaurora.org>