ARM: OMAP1: move omap1_bl pdata out of arch/arm/*

omap1 backlight platform data resides inside plat/board.h while it
should be inside include/linux/...
Move the omap1 backlight platform data to
include/linux/platform_data/.

Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>