net: stmmac: Correct the error message about invalid speed

The message about invalid speed does not state 1000 as a valid speed.
It is much simpler to said that the speed is invalid.

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