Staging: mt29f_spinand: Replace udelay function with usleep_range

Use 'usleep_range' instead of 'udelay' to elapse time. For
spinand_reset, define the upper limit by a factor of 2 to keep the wait
short while still allowing a "good enough" range for wakeup. Define the
range 250us - 1ms for spinand_cmdfunc to provide enough leeway before
issuing spinand_reset. Checkpatch found this issue.

CHECK: usleep_range is preferred over udelay; see
Documentation/timers/timers-howto.txt
Signed-off-by: Eva Rachel Retuya <eraretuya@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt29f_spinand/mt29f_spinand.c

@@ -736,7 +736,7 @@ static void spinand_reset(struct spi_device *spi_nand)
 		pr_info("spinand reset failed!\n");
 
 	/* elapse 1ms before issuing any other command */
-	udelay(1000);
+	usleep_range(1000, 2000);
 
 	if (wait_till_ready(spi_nand))
 		dev_err(&spi_nand->dev, "wait timedout!\n");
@@ -802,7 +802,7 @@ static void spinand_cmdfunc(struct mtd_info *mtd, unsigned int command,
 		if (wait_till_ready(info->spi))
 			dev_err(&info->spi->dev, "WAIT timedout!!!\n");
 		/* a minimum of 250us must elapse before issuing RESET cmd*/
-		udelay(250);
+		usleep_range(250, 1000);
 		spinand_reset(info->spi);
 		break;
 	default: