Correct the irq for spacecast phy.

The current mdiobus_register does not seem to make use of irq array.
That is probably the reason this error is not affecting anything. To be
consistent with the change on phy_id, this field is also updated in case
modiobus_register will use it later.

Change-Id: I49b4363eececc54e173a753207d7db0355c817cc
1 file changed