regulator: Add property for I2C level shifter

By setting nxp,i2c-lt-enable the I2C level translator is
enabled.

Signed-off-by: Per-Daniel Olsson <[e-mail]>
Signed-off-by: Rickard x Andersson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

Documentation/devicetree/bindings/regulator/nxp,pca9450-regulator.yaml

···
       LDO5CTRL_L or LDO5CTRL_H register. Use this if the SD_VSEL signal is
       connected to a host GPIO.
 
+  nxp,i2c-lt-enable:
+    type: boolean
+    description:
+      Indicates that the I2C Level Translator is used.
+
 required:
   - compatible
   - reg