dt-bindings: usb: nxp,isp1760: add bindings

The nxp,isp1760 driver is old in the tree, but did not had a bindings
entry, since I am extend it to support isp1763 in the same family, use
this to add a proper yaml bindings file.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Link: https://lore.kernel.org/r/20210513084717.2487366-9-rui.silva@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>