usb: xhci-mtk: drop CONFIG_OF

The driver can match only the devices created by the OF core
via the DT table, so the table should be always used.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1616482975-17841-8-git-send-email-chunfeng.yun@mediatek.com


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