stmmac: fix a bug while checking the HW cap reg (v2)

The patch fixes a bug while checking the HW cap reg
on old MAC10/100 where this feature is not available.

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