dts: bindings: usb: Add enum to maximum-speed property

Add enum to list what values of maximum-speed are exceptable since
enum's get represented as strings in DT.  This also allows us to
generate a code enum to correspond to the string.

We also introduce include/dt-bindings/usb/usb.h which is a hand coded
definition of the enum.  We don't have a great way to generate this
right now, however it would be better if we did.

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
2 files changed