IBM OPAL Operator Panel Binding
-------------------------------
Required properties:
- compatible : Should be "ibm,opal-oppanel".
- #lines : Number of lines on the operator panel e.g. <0x2>.
- #length : Number of characters per line of the operator panel e.g. <0x10>.
Example:
oppanel {
compatible = "ibm,opal-oppanel";
#lines = <0x2>;
#length = <0x10>;
};