arm64: dts: qcom: add PMP8074 DTSI

PMP8074 is a companion PMIC to the Qualcomm IPQ8074 series that is
controlled via SPMI.

Add DTSI for it providing GPIO, regulator, RTC and VADC support.

RTC is disabled by default as there is no built-in battery so it will
loose time unless board vendor added a battery, so make it optional.

Signed-off-by: Robert Marko <robimarko@gmail.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220818221815.346233-4-robimarko@gmail.com