dt-bindings: rtc: zynqmp: Add support for Versal/Versal NET SoCs

dt-bindings: rtc: zynqmp: Add support for Versal/Versal NET SoCs

Add support for Versal and Versal NET SoCs. Both of them should use the
same IP core but differences can be in integration part that's why create
separate compatible strings.

Also describe optional power-domains property. It is optional because power
domain doesn't need to be onwed by non secure firmware hence no access to
control it via any driver.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/5ecd775e6083f86aa744c4e9dfb7f6a13082c78a.1709804617.git.michal.simek@amd.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>