net: phy: broadcom: Add power down exit reset state delay

Per the datasheet, when we clear the power down bit, the PHY remains in
an internal reset state for 40us and then resume normal operation.
Account for that delay to avoid any issues in the future if
genphy_resume() changes.

Fixes: fe26821 ("net: phy: broadcom: Wire suspend/resume for BCM54810")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/broadcom.c

@@ -399,6 +399,11 @@ static int bcm54xx_resume(struct phy_device *phydev)
 	if (ret < 0)
 		return ret;
 
+	/* Upon exiting power down, the PHY remains in an internal reset state
+	 * for 40us
+	 */
+	fsleep(40);
+
 	return bcm54xx_config_init(phydev);
 }