dt-bindings: interrupt-controller: arm,gic-v3: Describe EPPI range support

      be at least 4.

      The 1st cell is the interrupt type; 0 for SPI interrupts, 1 for PPI

      interrupts, 2 for interrupts in the Extended SPI range. Other values

      are reserved for future use.

      interrupts, 2 for interrupts in the Extended SPI range, 3 for the

      Extended PPI range. Other values are reserved for future use.

      The 2nd cell contains the interrupt number for the interrupt type.

      SPI interrupts are in the range [0-987]. PPI interrupts are in the

      range [0-15]. Extented SPI interrupts are in the range [0-1023].

      Extended PPI interrupts are in the range [0-127].

      The 3rd cell is the flags, encoded as follows:

      bits[3:0] trigger type and level flags.