dt-bindings: remove 'interrupt-parent' from bindings

'interrupt-parent' is often documented as part of define bindings, but
it is really outside the scope of a device binding. It's never required
in a given node as it is often inherited from a parent node. Or it can
be implicit if a parent node is an 'interrupt-controller' node. So
remove it from all the binding files.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/input/touchscreen/fsl-mx25-tcq.txt

@@ -8,7 +8,6 @@ Required properties:
  - reg: Memory range of the device.
  - interrupts: Should be the interrupt number associated with this module within
    the tscadc unit (<0>).
- - interrupt-parent: Should be a phandle to the tscadc unit.
  - fsl,wires: Should be '<4>' or '<5>'
 
 Optional properties: