usb: s3c-otg: Rename struct s3c_udc to dwc2_udc

The driver is actually for the Designware DWC2 controller.
This patch renames struct s3c_udc to struct dwc2_udc to make
things more obvious and clear.

Signed-off-by: Marek Vasut <marex@denx.de>
5 files changed