staging: hikey9xx: phy-hi3670-usb3: adjust retry logic

Instead of running a loop up to 100k times, add a small
delay inside it, running it up to 10 times, waiting up
to 100-200 us.

It should be noticed that I don't have the datasheet for
this PHY. So, not sure if this time will cover all
situations.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/b653d7d6073de176598a5026c41b1a845f360c9e.1611052729.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/hikey9xx/phy-hi3670-usb3.c

@@ -185,7 +185,7 @@ static int hi3670_phy_cr_start(struct regmap *usb31misc, int direction)
 static int hi3670_phy_cr_wait_ack(struct regmap *usb31misc)
 {
 	u32 reg;
-	int retry = 100000;
+	int retry = 10;
 	int ret;
 
 	while (retry-- > 0) {
@@ -198,6 +198,8 @@ static int hi3670_phy_cr_wait_ack(struct regmap *usb31misc)
 		ret = hi3670_phy_cr_clk(usb31misc);
 		if (ret)
 			return ret;
+
+		usleep_range(10, 20);
 	}
 
 	return -ETIMEDOUT;