'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: NRob Herring <robh@kernel.org>

Add three files. ralink,rt2880-net.txt  descibes the actual frame engine
and the other two describe the switch forntend bindings.
Signed-off-by: NJohn Crispin <blogic@openwrt.org>
Signed-off-by: NFelix Fietkau <nbd@openwrt.org>
Signed-off-by: NMichael Lee <igvtee@gmail.com>
Cc: devicetree@vger.kernel.org
Cc: David S. Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-mediatek@lists.infradead.org
Cc: John Crispin <blogic@openwrt.org>
Cc: Felix Fietkau <nbd@nbd.name>
Cc: Michael Lee <igvtee@gmail.com>
Cc: steven.liu@mediatek.com
Cc: Fred.Chang@mediatek.com
Patchwork: https://patchwork.linux-mips.org/patch/11970/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>