dt-bindings: interrupt-controller: update bindings for supporting more SoCs

Update bindings for Layerscape external irqs,
support more SoCs(LS1043A, LS1046A, LS1088A,
LS208xA, LX216xA)

Signed-off-by: Biwen Li <biwen.li@nxp.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20201130101515.27431-11-biwen.li@oss.nxp.com

Documentation/devicetree/bindings/interrupt-controller/fsl,ls-extirq.txt

 * Freescale Layerscape external IRQs
 
-Some Layerscape SOCs (LS1021A, LS1043A, LS1046A) support inverting
+Some Layerscape SOCs (LS1021A, LS1043A, LS1046A
+LS1088A, LS208xA, LX216xA) support inverting
 the polarity of certain external interrupt lines.
 
 The device node must be a child of the node representing the
@@ -8,12 +9,15 @@ Supplemental Configuration Unit (SCFG).
 
 Required properties:
 - compatible: should be "fsl,<soc-name>-extirq", e.g. "fsl,ls1021a-extirq".
+  "fsl,ls1043a-extirq": for LS1043A, LS1046A.
+  "fsl,ls1088a-extirq": for LS1088A, LS208xA, LX216xA.
 - #interrupt-cells: Must be 2. The first element is the index of the
   external interrupt line. The second element is the trigger type.
 - #address-cells: Must be 0.
 - interrupt-controller: Identifies the node as an interrupt controller
 - reg: Specifies the Interrupt Polarity Control Register (INTPCR) in
-  the SCFG.
+  the SCFG or the External Interrupt Control Register (IRQCR) in
+  the ISC.
 - interrupt-map: Specifies the mapping from external interrupts to GIC
   interrupts.
 - interrupt-map-mask: Must be <0xffffffff 0>.