soc: qcom: rpmh-rsc: Save base address of drv

Add changes to save drv's base address for rsc. This is
used to read drv's configuration such as solver mode is
supported or to write into CONTROL_TCS registers.

Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>