phy: phy-ralink-usb: convert to devm_platform_ioremap_resource

Use devm_platform_ioremap_resource to simplify code

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1604642930-29019-11-git-send-email-chunfeng.yun@mediatek.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>