ARM: dts: ts-4800: Add LCD support

This commit adds LCD support for the TS-4800. The panel is an Okaya
RS800480T-7X0WQ and the timings have been extracted from Technologic
Systems' tree.

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>