usb: gadget: s3c: use platform resources

The resources are correctly initialized, so just use them
instead of relying on hardcoded data from platform headers.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Felipe Balbi <balbi@kernel.org>
Link: https://lore.kernel.org/r/20200806182059.2431-8-krzk@kernel.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>