ARM: DT: STi: STiH407: Add sata DT nodes.

Now that the miphy28lp is upstream, we can add the sata dt nodes
for stih407 family silicon. This has been tested on b2120 board
J4 (sata0 channel). These nodes are disabled by default as a
special mini pci-e to sata daughter board is required which
isn't shipped with the board.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Maxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>