video: omapdss: Add opa362 driver

opa362 is amplifier for video and can be connected to the tvout pads
of the OMAP3. It has one gpio control for enable/disable of the output
(high impedance).

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Marek Belisko <marek@goldelico.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>