remoteproc: qcom_q6v5_mss: map/unmap MBA region before/after use

The application processor accessing the MBA region after assigning it to
the remote Q6 would lead to an XPU violation. Fix this by un-mapping the
MBA region post firmware copy and MBA text log dumps.

Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/1604473422-29639-2-git-send-email-sibis@codeaurora.org


[bjorn: Renamed "ptr" to "mba_region"]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>