coresight-tmc: allocate memory for register and buffer dump

Add code to allocate memory for dumping TMC register and buffer data.

These memory locations can be used to store TMC registers and buffer
information after a crash.

Change-Id: I8e98178110efa8e455a329e358c471757e87f2d1
Signed-off-by: Shashank Mittal <mittals@codeaurora.org>