omap: video: remove direct access of driver_data

dev_set/get_drvdata() should be used instead, as driver_data is going
away.

Cc: Imre Deak <imre.deak@nokia.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Trilok Soni <soni.trilok@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Felipe Contreras <felipe.contreras@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>