OMAP2xxx: hwmod: add I2C hwmods for OMAP2420, 2430

Add hwmod structures for I2C controllers on OMAP2420/2430.

NOTE: I2C module on OMAP2420 has 16bit registers and causes imprecise
aborts if 32bits are read/written to it.  Use the HWMOD_16BIT_REG flag
to notify the hmwod framework of this hard requirement so that
__raw_writew/readw is used to read /write the mdoule registers.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>