net: phy: export phy_queue_state_machine

We face the issue that link change interrupt and link status may be
reported by different PHY layers. As a result the link change
interrupt may occur before the link status changes.
Export phy_queue_state_machine to allow PHY drivers to specify a
delay between link status change interrupt and link status check.

v2:
- change jiffies parameter type to unsigned long

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Suggested-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>