omap24xx_i2c: add 2-byte address support

Various devices like EEPROMs require 2-byte address support to
be properly accessed. This patch adds this support for OMAP2/3/4
I2C controller driver.
I've tested it with EEPROM (16 bit address) and TPS65217 chip
(8 bit address) on TI Beaglebone board.

Unfortunately I don't have access to any compatible hardware
with 16bit data register so I can't test if those #ifdef
clauses really work.

CC: Tom Rini <trini@ti.com>
Signed-off-by: Ilya Yanok <ilya.yanok@cogentembedded.com>