renesas-ra/usb: Use interrupt rather than polling for usb task.

[andrewleech]

Summary

Most ports using TinyUSB now service the usb tasks from the usb interrupt. Based on issues reported in https://github.com/micropython/micropython/pull/14462#issuecomment-2251555449 I noticed the renesas port was still using the older polling pattern for this.

A quick test on a "EK-RA4W1 with usb cable patched on" I've got showed that the interrupt wrap approach appears to work correctly here, so submitted this change.

Testing

So far just flashing this change to "EK-RA4W1 with usb cable patched on" and tested that repl is still available in mpremote

The board I have uses the renesas full-speed peripheral, this change has not been tested on renesas board with high-speed usb.

[iabdalkader]

@andrewleech I finally had a chance to test this and USB is working fine with this change.

[andrewleech]

That's great thanks @iabdalkader

[dpgeorge]

Thanks @andrewleech, it's good to make all TinyUSB ports use the same mechanism.

And thanks to @iabdalkader for testing.