ARM: OMAP1: Use I2C bus registration helper for omap1

This patch starts using introduced I2C bus registration helper by cleaning
up registration currently done in various places and by doing necessary
board file modifications.

Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>