usb: imx21-hcd: set task state with schedule_timeout_uninterruptible()

imx21_hc_reset() uses schedule_timeout() without setting state to
STATE_(UN)INTERRUPTIBLE. As it is called in cycle without checking of
pending signals, use schedule_timeout_uninterruptible().

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>