karo: fdt: fix panel-dpi support

karo: fdt: fix panel-dpi support

commit fefe948bd273 ("karo: fdt: support 'panel-dpi' in DT")
inadvertedly copies the 'phandle' property from the 'display-timing'
node. This creates a new property in the 'panel-timing' node which
invalidates all FDT offsets being used by the
karo_fixup_panel_timing() routine.
Add a whitelist of properties to copy and recalculate all FDT offsets
after possible creation of a new property in the panel-timing node.
Also delete properties in the panel-timing node that don't exist in
the display-timings node.

Fixes: fefe948bd273 ("karo: fdt: support 'panel-dpi' in DT")