net: phy: phy_device: Call into the PHY driver to set LED blinking

Linux LEDs can be requested to perform hardware accelerated
blinking. Pass this to the PHY driver, if it implements the op.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>