usb: musb: Set the DT node on the child device

The musb glue drivers just copy the glue resources to the musb child device.
Instead, set the musb child device's DT node pointer to the parent device's
node so that platform_get_irq_byname() can find the resources in the DT.
This removes the need for statically populating the IRQ resources from the
DT which has been deprecated for some time.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211215230756.2009115-3-robh@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>