soc: qcom: rpmpd: Expand struct definition macros

Expand the struct definition macros to make things easier to see and
maintain. Now that the macros are unnecessary, remove them.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230313-topic-rpmpd-v3-5-06a4f448ff90@linaro.org