ARM: dts: ti: omap: omap3-devkit8000-lcd: Fix ti,keep-vref-on property to use correct...

ARM: dts: ti: omap: omap3-devkit8000-lcd: Fix ti,keep-vref-on property to use correct boolean syntax in DTS

The ti,keep-vref-on property, defined as a boolean flag in the Device
Tree schema, was incorrectly assigned a value (<1>) in the DTS file,
causing a validation error: "size (4) error for type flag". Remove
the value to match the schema and ensure compatibility with the driver
using device_property_read_bool(). This fixes the dtbs_check error.

Fixes: ed05637c30e6 ("ARM: dts: omap3-devkit8000: Add ADS7846 Touchscreen support")
Signed-off-by: Jihed Chaibi <jihed.chaibi.dev@gmail.com>
Link: https://lore.kernel.org/r/20250822225052.136919-1-jihed.chaibi.dev@gmail.com
Signed-off-by: Kevin Hilman <khilman@baylibre.com>