staging: regulator: hi6421v600-regulator: don't use usleep_range for off_on_delay

The regulator's core already handles it.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/4f17adca2b04c401e5de5556700638648ce25c0c.1597647359.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/hikey9xx/hi6421v600-regulator.c

@@ -73,9 +73,6 @@ static int hi6421_spmi_regulator_enable(struct regulator_dev *rdev)
 	struct hi6421v600_regulator *sreg = rdev_get_drvdata(rdev);
 	struct hi6421_spmi_pmic *pmic = sreg->pmic;
 
-	/* keep a distance of off_on_delay from last time disabled */
-	usleep_range(rdev->desc->off_on_delay, rdev->desc->off_on_delay + 1000);
-
 	dev_dbg(&rdev->dev, "%s: off_on_delay=%d us\n",
 		__func__, rdev->desc->off_on_delay);