soc: qcom: qcom_stats: Add support to read DDR statistic

soc: qcom: qcom_stats: Add support to read DDR statistic

DDR statistic provide different DDR LPM and DDR frequency statistic.
Add support to read from MSGRAM and display via debugfs.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Maulik Shah <maulik.shah@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250611-ddr_stats_-v5-1-24b16dd67c9c@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>