dt: Document general interrupt controller bindings

In order to use a device as interrupt controller, it needs to be marked
with the DT interrupt-controller property. This commit adds rudimentary
documentation about the required standard properties and describes the
most commonly used interrupt specifiers.

Cc: Linus Walleij <[email protected]>
Cc: Grant Likely <[email protected]>
Acked-by: Stephen Warren <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Thierry Reding <[email protected]>
Signed-off-by: Rob Herring <[email protected]>
1 file changed