usb: dwc3: meson-g12a: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20190802130408.20336-1-yuehaibing@huawei.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>