soc: qcom: socinfo: add file with SoC info format version

To ease debugging socinfo driver for newer chips add debugfs file
returning SoC info format version.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20200525164817.2938638-3-dmitry.baryshkov@linaro.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>