ARM: dts: stm32: Reinstate card detect behavior on DHSOM

The cd-gpios with (GPIO_ACTIVE_LOW | GPIO_PULL_UP) gpio is thus far
unsupported, reinstate the old cd-gpios behavior until this handling
is fully implemented. This permits the DHSOM to boot from SD again,
without this patch the card detect fails.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@st.com>