ARM: dts: STi: Remove "console=ttyASN" from bootargs for STi boards

As serial interface is already specified into stdout-path property,
"console=ttyASN,115200" from bootargs can be removed.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>