usb: usleep_range is preferred over udelay where wakeup is flexible

According to Documentation/timers/timers-howto.txt"
udelay() is only called once from a place where sleeping is allowed.
We can replace it with a call to usleep_range()
with a reasonable upper limit.

Signed-off-by: Sunny Kumar <sunny.kumar.roy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>