dt-bindings: interrupt-controller: Convert Broadcom STB L2 to YAML

Convert the Broadcom STB L2 generic Level 2 interrupt controller Device
Tree binding to YAML to help with validation.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20211208003727.3596577-10-f.fainelli@gmail.com


Signed-off-by: Rob Herring <robh@kernel.org>