net: mdio: mdio-bcm-unimac: Use read_poll_timeout

Simplify the code by using read_poll_timeout().
Signed-off-by: Justin Chen <justin.chen@broadcom.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20231213222744.2891184-3-justin.chen@broadcom.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/mdio/mdio-bcm-unimac.c

@@ -73,15 +73,10 @@ static inline void unimac_mdio_start(struct unimac_mdio_priv *priv)
 	unimac_mdio_writel(priv, reg, MDIO_CMD);
 }
 
-static inline unsigned int unimac_mdio_busy(struct unimac_mdio_priv *priv)
-{
-	return unimac_mdio_readl(priv, MDIO_CMD) & MDIO_START_BUSY;
-}
-
 static int unimac_mdio_poll(void *wait_func_data)
 {
 	struct unimac_mdio_priv *priv = wait_func_data;
-	unsigned int timeout = 100;
+	u32 val;
 
 	/*
 	 * C22 transactions should take ~25 usec, will need to adjust
@@ -89,14 +84,8 @@ static int unimac_mdio_poll(void *wait_func_data)
 	 */
 	udelay(30);
 
-	do {
-		if (!unimac_mdio_busy(priv))
-			return 0;
-
-		usleep_range(1000, 2000);
-	} while (--timeout);
-
-	return -ETIMEDOUT;
+	return read_poll_timeout(unimac_mdio_readl, val, !(val & MDIO_START_BUSY),
+				 2000, 100000, false, priv, MDIO_CMD);
 }
 
 static int unimac_mdio_read(struct mii_bus *bus, int phy_id, int reg)