USB/host: Bugfix: Return length of copied buffer in uhci_hub_control()

In addition to the error statuses -ETIMEDOUT and -EPIPE, uhci_hub_control()
needs to return the length of copied buffer when appropriate, so that the
returned status of ->hub_control() in rh_call_control() in the USB core
HCD can be properly handled.

This patch also removes the OK() macro to make the code more readable.

Reviewed-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>