Staging: olpc_dcon: change to msleep to usleep_range

The resolution of msleep is related to HZ, so with HZ set to
100 any msleep of less then 10ms will become ~10ms. This is
not what we want. Use usleep_range to get more control of
what is happening here.
Signed-off-by: Jens Frederich <jfrederich@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/olpc_dcon/olpc_dcon.c

@@ -131,13 +131,13 @@ static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
 			pr_warn("unable to force dcon to power up: %d!\n", x);
 			return x;
 		}
-		msleep(10); /* we'll be conservative */
+		usleep_range(10000, 11000);  /* we'll be conservative */
 	}
 
 	pdata->bus_stabilize_wiggle();
 
 	for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
-		msleep(1);
+		usleep_range(1000, 1100);
 		x = dcon_read(dcon, DCON_REG_ID);
 	}
 	if (x < 0) {