ARM: OMAP3: Remove unused CONFIG_I2C2_OMAP_BEAGLE

There is no CONFIG_I2C2_OMAP_BEAGLE in mainline and it is under
removal in linux-omap also so remove this dead code now.

Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>