ARM: dts: stm32: Fix GPIO hog flags on DHCOM DRC02

The GPIO hog flags are ignored by gpiolib-of.c now, set the flags to 0.
Since GPIO_ACTIVE_HIGH is defined as 0, this change only increases the
correctness of the DT.

Fixes: fde180f0 ("ARM: dts: stm32: Add DHSOM based DRC02 board")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>