ARM: dts: STiH407-family: sti sound card field cleaning

Cleaning of some uni-players and uni-reader fields.
Associated configurations are now handled in driver based
on compatible string.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>