usb: mtu3: reinitialize CSR registers

The CSR registers will be reset as default value if the
ports are disabled, so reinitialize them when the ports
are enabled again.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1595834101-13094-3-git-send-email-chunfeng.yun@mediatek.com


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