dt-bindings: optee driver interrupt can be a per-cpu interrupt

Explicit in optee firmware device tree bindings that the interrupt
used by optee driver for async notification can be a peripheral
interrupt or a per-cpu interrupt.

Signed-off-by: Etienne Carriere <[e-mail]>
Reviewed-by: Sumit Garg <[e-mail]>
Signed-off-by: Jens Wiklander <[e-mail]>

Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.yaml

···
     maxItems: 1
     description: |
       This interrupt which is used to signal an event by the secure world
-      software is expected to be edge-triggered.
+      software is expected to be either a per-cpu interrupt or an
+      edge-triggered peripheral interrupt.
 
   method:
     enum: [smc, hvc]