ARM: STi: DT: Add STiH407 family tsin0 pinctrl configuration

tsin0 and be configured as either serial or parallel. This patch
adds the pinctrl config for both possiblities. On B2120 reference
design tsin0 is brought out as TSA on the NIMA slot of the B2004A
daughter board.

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