ARM: dts: socfpga: Drop LED node from VINING FPGA

Drop the LED node from VINing FPGA DT because the LED wiring is
different on each mainboard revision. This wiring is therefore
handled in mainboard DT Overlays.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>