firmware: qcom: scm: Convert to streaming DMA APIS

firmware: qcom: scm: Convert to streaming DMA APIS

This patch converts the Qualcomm SCM driver to use the streaming DMA APIs
for communication buffers.  This is being done so that the
secure_flush_area call can be removed.  Using the DMA APIs will also make
the SCM32 symmetric to the coming SCM64 code.

Signed-off-by: Andy Gross <andy.gross@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>