ARM: STi: DT: STiH416: Change miphy356 node name to phy@fe382000

Following Arnds review comments, update the miphy365 to follow the
common convention of naming the phy node names as phy@addr.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>