arm64: dts: qcom: sdm845-db845c: enable rradc

Enable the Round Robin ADC for the db845c.

Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221016180330.1912214-4-caleb.connolly@linaro.org