ARM: dts: stm32: fix pwr regulators references to use scmi

Fixes stm32mp15*-scmi DTS files introduced in [1] to also access PWR
regulators through SCMI service. This is needed since enabling secure
only access to RCC clock and reset controllers also enables secure
access only on PWR voltage regulators reg11, reg18 and usb33 hence
these must also be accessed through SCMI Voltage Domain protocol.
This change applies on commit [2] that already corrects issues from
commit [1].

Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Link: [1] https://lore.kernel.org/linux-arm-kernel/20220422150952.20587-7-alexandre.torgue@foss.st.com
Link: [2] https://lore.kernel.org/linux-arm-kernel/20220613071920.5463-1-alexandre.torgue@foss.st.com


Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>