net: phy: rtl8211: fix interrupt on status link change

This is to fix a problem in the rtl8211 where the driver
wasn't properly enabled the interrupt on link change status.
it has to enable the ineterrupt on the bit 10 in the register 18
(INER).

Reported-by: Sharma Bhupesh <B45370@freescale.com>
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>