'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>

This patch adds documentation of device tree bindings for the Synopsys
DesignWare AXI DMA controller.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>