ARM: dts: Fix STi boards compatibles

The compatible strings have to be ordered from specific to generic.
This patch fixes this for STi boards, which did the exact opposite.

Cc: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>