Staging: iio: light: Use usleep_range instead of msleep

This patch fixes following checkpatch.pl warning:

WARNING: msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt
Signed-off-by: Vaishali Thakkar <vthakkar1994@gmail.com>
Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/iio/light/isl29018.c

@@ -563,7 +563,7 @@ static int isl29018_chip_init(struct isl29018_chip *chip)
 		return status;
 	}
 
-	msleep(1);	/* per data sheet, page 10 */
+	usleep_range(1000, 2000);	/* per data sheet, page 10 */
 
 	/* set defaults */
 	status = isl29018_set_range(chip, chip->range, &new_range);