spi: core: Replace msleep with usleep_range to get more accurate sleep time

Fixes below checkpatch warning:
WARNING: msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt
+               msleep(10);
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi.c

@@ -892,7 +892,7 @@ static int spi_stop_queue(struct spi_master *master)
 	 */
 	while ((!list_empty(&master->queue) || master->busy) && limit--) {
 		spin_unlock_irqrestore(&master->queue_lock, flags);
-		msleep(10);
+		usleep_range(10000, 11000);
 		spin_lock_irqsave(&master->queue_lock, flags);
 	}