net: mvmdio: disable interrupts in driver failure path

When the mvmdio driver has an interrupt, it enables the "done" interrupt
after requesting its interrupt handler.  However, probe failure results
in the interrupt being left enabled.  Disable it on the failure path.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>