remoteproc: qcom_q6v5_mss: Add MBA log extraction support

remoteproc: qcom_q6v5_mss: Add MBA log extraction support

On SC7180 the MBA firmware stores the bootup text logs in a 4K segment
at the beginning of the MBA region. Add support to extract the logs
which will be useful to debug mba boot/authentication issues.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/20200721112935.25716-3-sibis@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>