usb: phy-ulpi-viewport: convert to readl_poll_timeout_atomic()

Use readl_poll_timeout_atomic() to simplify code
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1600668815-12135-8-git-send-email-chunfeng.yun@mediatek.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/phy/phy-ulpi-viewport.c

@@ -7,6 +7,7 @@
 #include <linux/kernel.h>
 #include <linux/usb.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/usb/otg.h>
 #include <linux/usb/ulpi.h>
 
@@ -20,16 +21,9 @@
 
 static int ulpi_viewport_wait(void __iomem *view, u32 mask)
 {
-	unsigned long usec = 2000;
+	u32 val;
 
-	while (usec--) {
-		if (!(readl(view) & mask))
-			return 0;
-
-		udelay(1);
-	}
-
-	return -ETIMEDOUT;
+	return readl_poll_timeout_atomic(view, val, !(val & mask), 1, 2000);
 }
 
 static int ulpi_viewport_read(struct usb_phy *otg, u32 reg)