ARM: dts: stm32: Drop duplicate status okay from DHCOM gpioc node

The stm32mp15xxaa-pinctrl.dtsi included in stm32mp15xx-dhcom-som.dtsi
already sets status = "okay" in gpioc: gpio@50004000 node, drop the
duplicate from stm32mp15xx-dhcom-som.dtsi . No functional change.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
Cc: kernel@dh-electronics.com
Cc: linux-stm32@st-md-mailman.stormreply.com
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>