i2c: quick and dirty eeprom reader

Partial implementation of omap_i2c_read() and the skeleton of
part of an eeprom driver. This isn't production ready, but it
shows that the initialization code works.

Tested on the BBB. Will try the xM soon.

Change-Id: I48e9fe836772a34a2e9d09e4a0b82a2bd7b24182