ARM: dts: s5p: Fix DTC unit name warnings in SMDKv210 board

Fix following DTC warnings in SMDKv210 board:

Warning (unit_address_vs_reg): Node /soc/fimd@f8000000/display-timings/timing@0 has a unit name, but no reg property

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>