ETHCK_K is the identifier the kernel clock for ETH in kernel
binding, selected by ETHKSELR / gated by ETHCKEN = BIT(7).
U-Boot driver need to use the same identifier, so change ETHCK
to ETHCK_K.
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com> Signed-off-by: Christophe Roullier <christophe.roullier@st.com>