cat24c256: driver for the cat24c256 i2c eeprom

Change-Id: I27107681d3821ea6d4b0f88bcd8da2f7f3d51dd2
eepromread: simple program to view eeprom contents

This program uses the i2c /dev interface to read the
contents of EEPROMs and display it to the user in
HEX and ASCII. It also has a mode that can display
data in label:value pairs. That mode is used for
board detection in the rc script to start the right
i2c drivers for the board.

Change-Id: I3e8c56de851b3488f4752d360347b9706b1f0531