soc: qcom: socinfo: move SMEM item struct and defines to a header

Move SMEM item struct and related defines to a header in order to be able
to reuse them in the SMEM driver instead of duplicating them.

Signed-off-by: Robert Marko <robimarko@gmail.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230526204802.3081168-1-robimarko@gmail.com