net: phy: Use threaded IRQ, to allow IRQ from sleeping devices

The interrupt lines from PHYs maybe connected to I2C bus expanders, or
from switches on MDIO busses. Such interrupts are sourced from devices
which sleep, so use threaded interrupts. Threaded interrupts require
that the interrupt requester also uses the threaded API. Change the
phylib to use the threaded API, which is backwards compatible with
none-threaded IRQs.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>