Hi Bhamy,
The issues is barebox, can´t not parse device tree, Let the imx-ldb.c code in the kernel to probe and *add* a way to parse the device-tree for adding mode timing property using the display-timing stuff. (this means kernel patch)
or Look for a common timings from an existing displays in simple-panel.c and pass them to the compatibile property of the panel in the device-tree via bootloader. however unfortunately barebox is not supported.