* Generic Mailbox Controller and client driver bindingsGeneric binding to provide a way for Mailbox controller drivers toassign appropriate mailbox channel to client drivers.* Mailbox ControllerRequired property:- #mbox-cells: Must be at least 1. Number of cells in a mailbox specifier.Example: mailbox: mailbox { ... #mbox-cells = <1>; };* Mailbox ClientRequired property:- mboxes: List of phandle and mailbox channel specifiers.Optional property:- mbox-names: List of identifier strings for each mailbox channel required by the client. The use of this property is discouraged in favor of using index in list of 'mboxes' while requesting a mailbox. Instead the platforms may define channel indices, in DT headers, to something legible.Example: pwr_cntrl: power { ... mbox-names = "pwr-ctrl", "rpc"; mboxes = <&mailbox 0 &mailbox 1>; };