The PSC sync change interrupt can fire multiple times while the link is
down, which is caused by noise on the serdes lines. As this isn't
information we make use of, it's pointless having the interrupt enabled.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>