coresight-tmc-etr: update higher order bits of trace buffer

ETR locates the trace location in system memory by using two
different register to obtain the full 40-bit address range.
This patch add capability for us to program the higher
8-bits.

Change-Id: I70128a3ad59157cc7728d024c19d8ebf3791e26a
Signed-off-by: Satyajit Desai <sadesai@codeaurora.org>
Signed-off-by: Rama Aparna Mallavarapu <aparnam@codeaurora.org>
Signed-off-by: Mulu He <muluhe@codeaurora.org>