dt-bindings: i2c: st,stm32-i2c: add 'power-domains' property

STM32 I2C may be in a power domain which is the case for the STM32MP2x
based boards. Allow a single 'power-domains' entry for STM32 I2C.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20251215-stm32-i2c-mp2x-dt-updates-v1-1-2738a05a7af8@foss.st.com
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

Author: Alain Volmat

Documentation/devicetree/bindings/i2c/st,stm32-i2c.yaml

@@ -127,6 +127,9 @@ properties:
 
   wakeup-source: true
 
+  power-domains:
+    maxItems: 1
+
   access-controllers:
     minItems: 1
     maxItems: 2