usbip: fix usbip attach to find a port that matches the requested speed

usbip attach fails to find a free port when the device on the first port
is a USB_SPEED_SUPER device and non-super speed device is being attached.
It keeps checking the first port and returns without a match getting stuck
in a loop.

Fix it check to find the first port with matching speed.

Reported-by: Juan Zea <juan.zea@qindel.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>