phy: IC+101G and PHY_HAS_INTERRUPT flag

This patch adds the PHY_HAS_INTERRUPT flag for IC+101 device series.
Also the patch does a simple dity-up to signal that
the driver actually is for IP101A LF and IP101G devices.
In fact, these are two similar PHYs that have the same IDs
and mainly differ for the EEE capability supported in the
G series.

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