MIPS: ralink: use the dwc2 driver for the rt305x USB controller

This sets up the devicetree file for the rt3050 chip series and rt3052
eval board to use the right compatible string for the dwc2 driver.

Acked-by: John Crispin <blogic@openwrt.org>
Cc: blogic@openwrt.org
Cc: linux-mips@linux-mips.org
Cc: Matthijs Kooijman <matthijs@stdin.nl>
Patchwork: https://patchwork.linux-mips.org/patch/5226/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>