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: NPaul Walmsley <paul@pwsan.com>
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>