ARM: OMAP2: Add pinmux support for omap34xx

This patch adds pinmux support for OMAP3. Incorporated review comments
from Tony to make mux_value as bit mask. Tested on 3430SDP.

Also merge in adding of I2C pins from Jarkko Nikula.

Acked-by: Anand Gadiyar <gadiyar@ti.com>
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>